Servo Blog

Servo is now available on crates.io

2026-04-13T00:00:00Z

Today the Servo team has released v0.1.0 of the servo crate. This is our first crates.io release of the servo crate that allows Servo to be used as a library.

We currently do not have any plans of publishing our demo browser servoshell to crates.io. In the 5 releases since our initial GitHub release in October 2025, our release process has matured, with the main “bottleneck” now being the human-written monthly blog post. Since we’re quite excited about this release, we decided to not wait for the monthly blog post to be finished, but promise to deliver the monthly update in the coming weeks.

As you can see from the version number, this release is not a 1.0 release. In fact, we still haven’t finished discussing what 1.0 means for Servo. Nevertheless, the increased version number reflects our growing confidence in Servo’s embedding API and its ability to meet some users’ needs.

In the meantime we also decided to offer a long-term support (LTS) version of Servo, since breaking changes in the regular monthly releases are expected and some embedders might prefer doing major upgrades on a scheduled half-yearly basis while still receiving security updates and (hopefully!) some migration guides. For more details on the LTS release, see the respective section in the Servo book.

February in Servo: faster layout, pause and resume scripts, and more!

2026-03-31T00:00:00Z

Servo 0.0.6 includes some exciting new features:

<button command> and <button commandfor> (@lukewarlow, #41237)
‘:modal’ selectors on <dialog> (@lukewarlow, #42201)
‘@property’ rules (@yezhizhen, @Loirooriol, #42136, #42858)
‘alignment-baseline’ and ‘baseline-shift’ (@Loirooriol, #42361)
‘Content-Security-Policy: base-uri’ (@WaterWhisperer, #42272)
partial support for <iframe loading=lazy> (@TimvdLippe, #41959)
partial support for ‘transform-style: preserve-3d’ (@simonwuelker, #42755)

Plus a bunch of new DOM APIs:

most of the Pointer Events API (@webbeef, #41290)
the UserActivation API (@stevennovaryo, #42060)
import.meta.resolve() (@Gae24, #42506)
integrity in <script type=importmap> (@Gae24, #42604)
the formData() method on Request (@Taym95, #42041)
the alpha property on HTMLInputElement (@simonwuelker, #42293)
tabIndex on HTMLElement and SVGElement (@mrobinson, @Loirooriol, #42913)
fullscreenElement on Document and ShadowRoot (@onsah, #42401)
toJSON() on PerformancePaintTiming (@shubhamg13, #42396)
navigator.pdfViewerEnabled (@simonwuelker, #42277)
keyPath on IDBIndex (@arihant2math, #42431)
createIndex(), deleteIndex(), and index() on IDBObjectStore (@arihant2math, @bulltickr, #38840, #42440, #42443)

` with `

This is a big update, so here’s an outline:

Work in progress
– accessibility, execCommand()
Developer tools
– localhost only by default, Inspector, Console, Debugger
servoshell
– servo:config, F5 to reload
Embedding API
– offline builds, user stylesheets, context menus, gamepad API
More on the web platform
– font fallback, cookies, IndexedDB, First and Largest Contentful Paint
Performance and stability
– about:memory, incremental layout, shared memory
Bug fixes
– Windows arm64, layout, DOM events, shadow DOM
Donations
– how you can help Servo flourish

Work in progress

We’ve started working on accessibility support for web content (@alice, @delan, #42333, #42402), gated by a pref (--pref accessibility_enabled). Each webview will be able to expose its own accessibility tree, which the embedder can then integrate into its own accessibility tree. As part of this work:

AccessKit now supports combining accessibility trees with its new “subtree” feature (@DataTriny, @delan, @lukewarlow, @alice, AccessKit/accesskit#655, AccessKit/accesskit#641)
egui has been migrated to the new AccessKit API (@delan, @lukewarlow, @lucasmerlin, @DataTriny, emilk/egui#7850)
we added a Servo API for activating accessibility features (@delan, @alice, #42336), although this has since become a WebView API

We’ve started implementing document.execCommand() (@TimvdLippe, #42621, #42626, #42750), gated by a pref (--pref dom_exec_command_enabled). This feature is also enabled in experimental mode, and together with contenteditable, it’s critical for rich text editing on the web. The work done in February includes:

document.queryCommandEnabled() (@TimvdLippe, #42634)
document.queryCommandSupported() (@TimvdLippe, #42731)
document.queryCommandIndeterm(), queryCommandState(), and queryCommandValue() (@TimvdLippe, #42748)
the canonicalize whitespace algorithm – this is used by the ‘delete’, ‘forwardDelete’, and ‘insertText’ commands (@TimvdLippe, #42704)
contentEditable on HTMLElement – for execCommand() only, excluding any support for interactive editing (@TimvdLippe, #42633, #42734)

Developer tools

DevTools has seen some big improvements in February!

When enabled in servoshell, the DevTools server is more secure by default, listening only on localhost when only a port number is specified (@Narfinger, #42502). You can open the port for remote debugging by passing a full SocketAddr, such as --devtools=[::]:6080 or --devtools=0.0.0.0:6080.

In the Inspector tab, you can now edit DOM attributes, and the DOM tree updates when attributes change (@simonwuelker, #42601, #42785). You can now list the event type and phase of event listeners attached to a DOM node as well (@simonwuelker, #42355).

In the Console tab, objects can now be previewed when passed to console.log() and friends (@simonwuelker, #42296, #42510, #42752), and boolean values are now syntax highlighted (@pralkarz, #42513).

In the Debugger tab, you can now pause and resume script execution, both manually and when breakpoints are hit (@eerii, @atbrakhi, #42599, #42580, #42874). We’ve also started working on other debugger features (@atbrakhi, @eerii, #42306), including stepping execution (@eerii, @atbrakhi, #42844, #42878, #42906), so once again stay tuned!

Servo 0.0.6 showing DevTools debugger setting breakpoints, pausing on those breakpoints, and resuming script execution

servoshell

Back in August, we added a servo:preferences page to servoshell that allows you to set some of Servo’s most common preferences at runtime (@jdm, #38159).

servoshell now has a servo:config page (@arihant2math, #40324), allowing you to set any preference, even internal ones. Note that preference changes are not yet persistent, and not all prefs take effect when changed at runtime.

You can now press F5 to reload the page in servoshell (@Narfinger, #42538), in addition to pressing Ctrl+R or ⌘R.

We’ve fixed a regression where the caret stopped being visible in the location bar (@mrobinson, #42470).

Embedding API

Servo is now easier to build offline, using the complete source tarball included in each release (@jschwe, #42852). Go to a release on GitHub, then download servo-[version]-src-vendored.tar.gz to get started.

You can now add and remove user stylesheets with UserContentManager::add_stylesheet and remove_stylesheet, and remove user scripts with UserContentManager::remove_script (@mukilan, #42288). Previously user stylesheets were only configurable via servoshell’s --user-stylesheet option.

Before opening any context menus on behalf of web content, Servo now closes any context menus that were opened by web content (@mrobinson, #42487), to avoid UI problems on some platforms. This is done by calling WebViewDelegate::hide_embedder_control before calling show_embedder_control in those cases.

Input method events from web content now indicate whether or not the virtual keyboard should be shown (@stevennovaryo, @mrobinson, #42467), with the new InputMethodControl::allow_virtual_keyboard method. Generally the virtual keyboard should only be shown when the page has sticky activation.

We’re reworking our gamepad API, with WebViewDelegate::play_gamepad_haptic_effect and stop_gamepad_haptic_effect being replaced by a new API that (as of the end of February at least) is known as GamepadProvider (@atbrakhi, #41568). The old methods are no longer called (#43743), and may be removed at some point.

We now have better diagnostic output when we fail to create an OpenGL context (@mrobinson, #42873), including when the OpenGL versions supported by the device are too old.

Servo::constellation_sender was removed (@jdm, #42389), since it was never useful to embedders.

We’ve also made some changes to Preferences:

devtools_server_port is now devtools_server_listen_address, and can now take either a port number (as before) or a full SocketAddr (@Narfinger, #42502)
dom_worklet_blockingsleep is now dom_worklet_blockingsleep_enabled (@mukilan, #42897)
Removed many unused preferences (@mukilan, #42897) – js_asyncstack, js_discard_system_source, js_dump_stack_on_debuggee_would_run, js_ion_offthread_compilation_enabled, js_mem_gc_allocation_threshold_avoid_interrupt_factor, js_mem_gc_allocation_threshold_factor, js_mem_gc_allocation_threshold_mb, js_mem_gc_decommit_threshold_mb, js_mem_gc_dynamic_heap_growth_enabled, js_mem_gc_dynamic_mark_slice_enabled, js_shared_memory, js_throw_on_asmjs_validation_failure, js_throw_on_debuggee_would_run, js_werror_enabled, and network_mime_sniff

More on the web platform

If you navigate to a video file or audio file as a document, the player now has controls (@webbeef, #42488).

Images now rotate according to their EXIF metadata by default (@rayguo17, #42567), like they would once we add support for ‘image-orientation: from-image’.

We’re implementing system-font-aware font fallback (@mrobinson, #42466), with support for this on macOS landing this month (@mrobinson, #42776). This allows Servo to render text in scripts that are not covered by web fonts or any of the fonts on Servo’s built-in lists of fallback fonts, as long as they are covered by fonts installed on the system.

Servo now supports the newer pointermove, pointerdown, pointerup, and pointercancel events (@webbeef, #41290). The older touchmove, touchstart, touchend, and touchcancel events continue to be supported.

The default language in ‘Accept-Language’ and navigator.language is now taken from the $LANG environment variable if present (@webbeef, #41919), rather than always being set to en-US.

<input type=color> now supports any CSS color value (@simonwuelker, #42275), including the more complex values like color-mix(). We’ve also landed the colorspace attribute (@simonwuelker, #42279), but only in the web-facing side of Servo for now, not the embedding API or in servoshell.

‘vertical-align’ is now a shorthand for ‘alignment-baseline’ and ‘baseline-shift’ (@Loirooriol, #42361), and scrollParent on HTMLElement is now a function per this recent spec update (@TimurBora, #42689).

Cookies are now more conformant (@sebsebmc, #42418, #42427, #42435). ‘Expires’ and ‘Max-Age’ attributes are now handled correctly in ‘Set-Cookie’ headers, get() and getAll() on CookieStore now trim whitespace in cookie names and values, and the behaviour of set() on CookieStore has been improved.

<iframe> elements are now more conformant in how load events are fired on the element and its contentWindow (@TimvdLippe, #42254), although there are still some bugs. This has long behaved incorrectly in Servo, and it has historically caused many problems in the Web Platform Tests.

IndexedDB is now more conformant in our handling of transactions (@Taym95, #41508, #42732), and when opening and closing connections (@gterzian, @Taym95, #42082, #42669).

We’ve started implementing Largest Contentful Paint timings (@shubhamg13, #42024), and we’ve landed a bunch of improvements to how First Contentful Paint timings work in Servo:

we now include ‘background-image’ (@shubhamg13, #42569)
we now include ‘border-image’ (@shubhamg13, #42581)
we now ignore subtrees with ‘opacity: 0’ (@shubhamg13, #42768)
we now ignore zero-sized subtrees (@shubhamg13, #42178)
we now ignore <iframe> (@shubhamg13, #42498)
we now ignore <video> and <video poster> unless they actually have an image (@shubhamg13, #42411)
we now ignore mouse moves when deciding when to stop measuring (@shubhamg13, #41999)

new WebSocket() now resolves relative URLs (@webbeef, #42425).

requestFullscreen() on Element now requires user activation (@stevennovaryo, #42060).

performance.getEntries() now returns PerformanceResourceTiming entries for navigations in <iframe> (@muse254, #42270).

When geolocation is enabled (--pref dom_geolocation_enabled), navigator.geolocation.getCurrentPosition() and watchPosition() now support the optional errors argument (@arihant2math, #42295).

We now support the ‘-webkit-text-security’ property in CSS (@mrobinson, #42181), which is not specified anywhere but required for MotionMark.

Performance and stability

Our about:memory page now knows how to report many new kinds of memory usage, including the DevTools server (@Narfinger, #42478, #42480), WebGL (@sagudev, #42570), localStorage and sessionStorage (@arihant2math, #42484), and some of the memory used by IndexedDB (@arihant2math, #42486). We’ve also started internally tracking the memory usage of the media subsystem (@Narfinger, #42504) and WebXR (@Narfinger, #42505).

Layout has seen a lot of performance work in February, with our main focus being on improving incremental layout of the box tree and fragment tree.

We now have our first truly incremental box tree layout (@mrobinson, @Loirooriol, @lukewarlow, #42700), rather than our previous “dirty roots”-based approach. Depending on how they were damaged, some boxes for floats (as above, #42816), independent formatting contexts (as above, #42783), and their descendants (as above, #42582) can now be reused, and they avoid damaging their parents (as above, #42847). We also destroy boxes with ‘display: none’ earlier in the layout process (as above, #42584).

Incremental fragment tree layout is improving too! Whereas we previously had to decide whether to run fragment tree layout in an “all or nothing” way, we can now reuse cached fragments in independent formatting contexts (@mrobinson, @Loirooriol, @lukewarlow, #42687, #42717, #42871). We can also measure how much work is being done on each layout (as above, #42817).

Servo uses shared memory for many situations where copying data over channels would be too expensive, such as for images and fonts. In multiprocess mode (--multiprocess), we use the operating system to create the shared memory in a way that can be shared with other processes, such as shm_open(3) or CreateFileMappingW, but this consumes resources that can sometimes be exhausted. We only need to use those kinds of shared memory in multiprocess mode, so we’ve reworked Servo to use Arc<Vec<u8>> in single-process mode (@Narfinger, #42083), which should avoid resource exhaustion.

Parsing web pages is complicated: we want pages to render incrementally as they stream in from the network, and we want to prefetch resources, but scripts can call document.write(), which injects markup “on the spot”. This is further complicated if that markup also contains a <script>.

We’ve recently landed some fixes to Servo’s async parser (@simonwuelker, #42882, #42910), which handles these issues more efficiently. This is currently an obscure and somewhat buggy feature (--pref dom_servoparser_async_html_tokenizer_enabled), but if we can get the feature working more reliably (#37418), it could halve the energy Servo spends on parsing, lower latency for pages that don’t use document.write(), and even improve the html5ever API for the ecosystem.

We’ve also landed optimisations for ‘Content-Security-Policy’ (@Narfinger, #42716), IntersectionObserver (@Narfinger, @mrobinson, @stevennovaryo, #42366, #42390), layout queries (@webbeef, #42327), the bfcache (@Narfinger, #42703), loading images (@Narfinger, #42684), and checks for multiprocess mode (@Narfinger, #42782), as well as the interfaces between Servo and SpiderMonkey (@sagudev, #42135, #42576).

We’ve continued our long-running effort to use the Rust type system to make certain kinds of dynamic borrow failures impossible (@Gae24, @pralkarz, @BryanSmith00, @sagudev, @Narfinger, @TimvdLippe, @kkoyung, @TimurBora, @onsah, #42342, #42294, #42370, #42417, #42619, #42616, #42637, #42640, #42662, #42679, #42681, #42665, #42667, #42699, #42712, #42725, #42729, #42726, #42720, #42738, #42737, #42735, #42751, #42805, #42809, #42780, #42820, #42715, #42635, #42880, #42846).

Bug fixes

We’ve landed some fixes for issues preventing Servo from being built on Windows arm64 (@dpaoliello, @npiesco, #42371, #42341). Work to enable Windows arm64 as a build platform is ongoing (@npiesco, #42312).

<img height> now takes the default <img width> from the aspect ratio of the image (@Loirooriol, #42577), rather than using a width of 300px by default. <svg width=0> and <svg height=0> now take the default width and height (respectively) from the aspect ratio of the <svg viewBox> (@Loirooriol, #42545).

We’ve fixed a bug in the result of layout queries, such as getBoundingClientRect(), on inline <svg> (@jdm, @Loirooriol, #42594), and we’ve fixed layout bugs related to ‘display: table-cell’ (@Loirooriol, #42778), ‘display: list-item’ (@Loirooriol, #42825, #42864), ‘inset: auto’ (@Loirooriol, #42586), ‘width: max-content’ (@mrobinson, @Loirooriol, @lukewarlow, #42574), ‘align-self: last baseline’ (@rayguo17, #42724), ‘list-style-image’ (@lukewarlow, #42332), ‘content: <image>’ (@lukewarlow, #42332), negative ‘margin’ (@Loirooriol, #42889), and ink overflow (@mrobinson, #42403).

HTML and CSS bugs:

Empty ‘url()’ values making requests when they shouldn’t (@rayguo17, #42622)
<template> failing to throw HierarchyRequestError when a DOM API is used to create an invalid hierarchy (@TimvdLippe, #42276)
<input> and <textarea> selection behaviour being incorrect when the text contains more than one script (@mrobinson, #42399)
<script nonce> validation failing to work correctly in some cases (@dyegoaurelio, #40956)
<a target> failing to work correctly after the related <iframe> is removed and a new one added with the same name (@jdm, #42344)
<base> not taking effect in some cases, or taking effect when given a data: or javascript: URL (@TimvdLippe, #42255, #42339)

JavaScript and DOM bugs:

event.target being incorrect on touchmove, touchend, and touchcancel events (@yezhizhen, #42654)
touchmove events not being fired when part of a two-finger pinch zoom (@yezhizhen, #42528)
touchend events erroneously firing after touchcancel events (@yezhizhen, #42654)
assignedNodes() on HTMLSlotElement returning incorrect results after the <slot> was removed from the shadow tree (@rayguo17, #42250)
Largest Contentful Paint timings no longer being collected after reloading or navigating (@shubhamg13, #41169)
PerformancePaintTiming being exposed to Worker globals when they shouldn’t be (@shubhamg13, #42409)
JavaScript modules resolved incorrectly when there are overlapping .imports or .scopes or import maps (@Gae24, #42668, #42630, #42754, #42821)
changes to how we trigger garbage collection breaking Speedometer (@sagudev, #42271)

WebDriver bugs:

Pointer actions and wheel actions behaving incorrectly when devicePixelRatio ≠ 1 (@yezhizhen, #42387, #42628)
Wheel actions throwing incorrect exceptions when they are missing properties (@yezhizhen, #42745)
pointerMove actions with non-zero duration failing to interleave with other actions (@yezhizhen, #42289)

We’ve fixed crashes in DevTools, in the Inspector tab (@eerii, @mrobinson, #42330), when exiting Servo while DevTools is connected (@simonwuelker, #42543), when setting breakpoints (@atbrakhi, #42810), and after clients disconnect (@simonwuelker, #42583).

We’ve fixed crashes in layout, when using ‘background-repeat: round’ (@mrobinson, #42303), when using ‘list-style-image’ or ‘content: <image>’ (@lukewarlow, #42332), when calling elementFromPoint() on Document (@mrobinson, @Loirooriol, @lukewarlow, #42822), and when handling layout queries like getBoundingClientRect() on inline <svg> (@jdm, @Loirooriol, #42594).

We’ve fixed crashes related to stylesheets, when removing stylesheets from the DOM (@TimvdLippe, #42273), when changing the href of a <link rel=stylesheet> (@TimvdLippe, #42481), and when loading stylesheets with --layout-threads=1 (@mrobinson, @Loirooriol, @lukewarlow, #42685).

We’ve also fixed crashes when using multitouch input (@yezhizhen, #42350), when using MediaStreamAudioSourceNode (@mrobinson, #42914), when calling add() on HTMLOptionsCollection (@mrobinson, #42263), when calling elementFromPoint() on Document or ShadowRoot(), when we fail to open a database for IndexedDB (@jdm, @mrobinson, #42444), and when certain pages are run with a mozjs debug build (@Gae24, #42428).

Donations

Thanks again for your generous support! We are now receiving 6985 USD/month (−0.4% from January) in recurring donations. This helps us cover the cost of our speedy CI and benchmarking servers, one of our latest Outreachy interns, and funding maintainer work that helps more people contribute to Servo.

Servo is also on thanks.dev, and already 32 GitHub users (–1 from January) that depend on Servo are sponsoring us there. If you use Servo libraries like url, html5ever, selectors, or cssparser, signing up for thanks.dev could be a good way for you (or your employer) to give back to the community.

We now have sponsorship tiers that allow you or your organisation to donate to the Servo project with public acknowlegement of your support. If you’re interested in this kind of sponsorship, please contact us at join@servo.org.

6985 USD/month

10000

Use of donations is decided transparently via the Technical Steering Committee’s public funding request process, and active proposals are tracked in servo/project#187. For more details, head to our Sponsorship page.

January in Servo: preloads, better forms, details styling, and more!

2026-02-28T00:00:00Z

Servo 0.0.5 is here, bringing with it lots of improvements in web platform features. Some highlights:

<link rel=preload> (@TimvdLippe, @jdm, #40059)
<style blocking> and <link blocking> (@TimvdLippe, #42096)
<img align> (@mrobinson, #42220)
<select disabled> (@simonwuelker, #42036)
OGG files can now be played in <audio> (@jdm, #41789)
‘cursor-color’ (@mrobinson, #41976)
‘content: <image>’ works on all elements (@andreubotella, #41480)
‘::details-content’ on <details> (@lukewarlow, #42107)
‘:open’ on <details> (@lukewarlow, #42195)
‘:active’ on <input type=button> (@mrobinson, #42095)
Origin API (@WaterWhisperer, #41712)
MouseEvent.detail (@mrobinson, #41833)
Request.keepalive (@TimvdLippe, @WaterWhisperer, #41457, #41811)
Cyclic imports, import attributes, and JSON modules (@Gae24, #41779)
navigator.sendBeacon() is enabled by default (@TimvdLippe, #41694)
https_proxy, HTTPS_PROXY, and NO_PROXY (@Narfinger, #41689)
ML-KEM, ML-DSA, and AES-OCB in Crypto (@kkoyung, #41604, #41617, #41615, #41627, #41628, #41647, #41659, #41676, #41791, #41822, #41813, #41829)

Web APIs

Servo now plays OGG media inside <audio> elements (@jdm, #41789)! We disabled this feature many years ago due to bugs in GStreamer, our media playback engine, but those bugs have since been fixed.

We now support non-px sizes for width and height attributes in <svg> elements (@rodio, #40761).

Inactive documents will now correctly reject fullscreen mode changes (@stevennovaryo, #42068).

We’ve enabled support for the navigator.sendBeacon() by default (@TimvdLippe, #41694); the dom_navigator_sendbeacon_enabled preference has been removed. As part of this work, we implemented the keepalive feature of the Request API (@TimvdLippe, @WaterWhisperer, #41457, #41811).

That’s not all for network-related improvements! Quota errors from the fetchLater() API provide more details (@TimvdLippe, #41665), and fetch response body promises now reject when invalid gzip content is encountered (@arayaryoma, #39438). Meanwhile, EventSource connections will no longer endlessly reconnect for permanent failures (@WaterWhisperer, #41651, #42137), and now use the correct ‘Last-Event-Id’ header when reconnecting (@WaterWhisperer, #42103). Finally, Servo will create PerformanceResourceTiming entries for requests that returned unsuccessful responses (@bellau, #41804).

There has been lots of work related to navigating pages and loading iframes. We process URL fragments more consistently when navigating via window.location (@TimvdLippe, #41805, #41834), and allow evaluating javascript: URLs when a document’s domain has been modified (@jdm, #41969). XML documents loaded in an <iframe> no longer inherit their encoding from the parent document (@simonwuelker, #41637).

We’re also made it possible to use blob: URLs from inside ‘about:blank’ and ‘about:srcdoc’ documents (@jdm, #41966, #42104). Finally, constructed documents (e.g. new Document()) now inherit the origin and domain of the document that created them (@TimvdLippe, #41780), and we implemented the new Origin API (@WaterWhisperer, #41712).

Servo’s mixed content protections are steadily increasing. Insecure requests (e.g. HTTP) originating from <iframe> elements can now be upgraded to secure protocols (@WaterWhisperer, #41661), and redirected requests now check the most recent URL when determining if the protocol is secure (@WaterWhisperer, #41832).

<style blocking> and <link blocking> can now be used to block rendering while loading stylesheets that are added dynamically (@TimvdLippe, #42096), and stylesheets loaded when parsing the document will block the document ‘load’ event more consistently (@TimvdLippe, @mrobinson, #41986, #41987, #41988, #41973). We also fire the ‘error’ event if a fetched stylesheet response is invalid (@TimvdLippe, @mrobinson, #42037).

Servo now leads other browsers in support for new Web Cryptography algorithms! This includes full support for ML-KEM (@kkoyung, #41604, #41617, #41615, #41627), ML-DSA (@kkoyung, #41628, #41647, #41659, #41676), and AES-OCB (@kkoyung, #41791, #41822, #41813, #41829), plus improvements to AES-GCM (@kkoyung, #41950). Additionally, the error messages returned by many Crypto APIs are now more detailed (@PaulTreitel, @danilopedraza, #41964, #41468, #41902).

JS module loading received a lot of attention – we’ve improved support for cyclic imports (@Gae24, #41779), import attributes (@Gae24, #42185), and JSON modules (@Gae24, @jdm, #42138).

Additionally, the <link rel=preload> attribute now triggers preload fetch operations that can improve page load speeds (@TimvdLippe, @jdm, #40059).

IndexedDB support continues to make progress, though for now the feature is disabled by default (--pref dom_indexeddb_enabled). This month we gained improvements to connection queues (@gterzian, #41500, #42053) and request granularity (@gterzian, #41933).

We were accidentally persisting SessionStorage data beyond the current session, but this has been corrected (@arihant2math, #41326).

Text input fields have received a lot of love this month. Clicking in an input field will position the cursor accordingly (@mrobinson, @jdm, @Loirooriol, #41906, #41974, #41931), as will clicking past the end of a multiline input (@mrobinson, @Loirooriol, #41909). Selecting text with the mouse in input fields works (@mrobinson, #42049), and double and triple clicks now toggle selections (@mrobinson, #41926). Finally, we fixed a bug causing the input caret to be hidden in <input> elements inside of Shadow DOM content (@stevennovaryo, #42233).

‘cursor-color’ is respected when rendering the input cursor (@mrobinson, #41976), and newlines can no longer be pasted into single line inputs (@mrobinson, #41934). Finally, we fixed a panic when focusing a text field that is disabled (@mrobinson, #42078), as well as panics in APIs like HTMLInputElement.setRangeText() that confused bytes and UTF-8 character indices (@mrobinson, #41588).

We also made time to improve form controls! The default styling of many controls received some care (@mrobinson, #42085), while <input type=button> can now be styled with the ‘:active’ pseudo-class (@mrobinson, #42095). Conversely, disabled <select> elements can no longer be activated (@simonwuelker, #42036).

Mouse events triggered by the embedder are more complete; MouseEvent.detail correctly reports the click count for ‘mouseup’ and ‘mousedown’ events (@mrobinson, #41833), and many other members are now consistent with other mouse events (@mrobinson, #42013).

Performing a pinch zoom on mobile is now reflected in the VisualViewport API (@stevennovaryo, #41754), though for now the feature is disabled by default (--pref dom_visual_viewport_enabled).

We’ve changed the behaviour of Web APIs that use the [Clamp] annotation (such as Blob.slice()). The previous implementation would cast floating point values to their integer equivalents, but the standard requires more specific rounding logic (@Taym95, #41640).

The RGBA8 constant is now available in WebGL 1 rendering contexts; it was previously only available in WebGL 2 contexts (@simonwuelker, #42048).

Fonts were another area of focus this month. Loading web fonts from file: URLs works as expected (@TimvdLippe, #41714), as does using web fonts within Shadow DOM content (@minghuaw, #42151). Each web font request now creates a PerformanceResourceTiming entry (@lumi-me-not, #41784). Servo supports font variations as of November 2025, so as of this month, the FontFace constructor no longer ignores the ‘font-variation-settings’ property (@muse254, #41968).

Cursive scripts now ignore the ‘letter-spacing’ CSS property (@mrobinson, #42165), and we significantly reduced the time and memory required when rendering non-ASCII text (@mrobinson, @Loirooriol, #42105, #42162) and when text nodes share the same font (@mrobinson, #41876).

CSS

There were lots of improvements to block layout algorithms (@Loirooriol, #41492, #41624, #41632, #41655, #41652, #41683). These often affect pages where a block element (such as a <div>) exists within some other layout mode (such as an inline <span>, or a flexbox context), and fixes like these ensure Servo matches the output of other browsers.

Elements with scrollable overflow can be scrolled more consistently, even with CSS transforms applied to them (@stevennovaryo, #41707, #42005).

You can now use ‘content: <image>’ on any element (@andreubotella, #41480). Generated image content used to only work with pseudo-elements, but that restriction no longer applies.

<details> elements can now be styled with the ‘::details-content’ pseudo-element (@lukewarlow, #42107), as well as the ‘:open’ pseudo-class (@lukewarlow, #42195).

CSS styles now inherit correctly through ‘display: contents’ as well as <slot> elements in Shadow DOM content (@longvatrong111, @Loirooriol, @mrobinson, #41855).

‘overflow-clip-margin’ now works correctly when ‘border-radius’ is present (@Loirooriol, #41967).

We fixed bugs involving text inside flexbox elements: they now use consistent baselines for alignment (@lukewarlow, @mrobinson, #42038), and style updates are propagated to the text correctly (@mrobinson, #41951).

<img align> now aligns the image as expected (@mrobinson, #42220).

‘word-break: keep-all’ now prevents line breaks in CJK text (@RichardTjokroutomo, #42088).

We also fixed some bugs involving floats, collapsing margins, and phantom line boxes (@Loirooriol, #41812), which sound much cooler than they actually are.

Finally, we upgraded our Stylo dependency to the latest changes as of January 1 2026 (@Loirooriol, #41916, #41696). Stylo powers our CSS parsing and style resolution engine, and this upgrade improves support for parsing color functions like ‘color-mix()’, and improves our CSS animations and transitions for borders and overflow clipping.

Automation and introspection

Last month Servo gained support for HTTP proxies. We now support HTTPS proxies as well (@Narfinger, #41689), which can be configured with the https_proxy or HTTPS_PROXY environment variables, or the network_https_proxy_uri preference. In addition, the NO_PROXY environment variable or the network_http_no_proxy preference can disable any proxy for particular domains.

Our developer tools integration continues to improve. Worker globals are now categorized correctly in the UI (@atbrakhi, #41929), and the Sources panel is populated for very short documents (@atbrakhi, #41983). Servo will report console messages that were logged before the developer tools are opened (@eerii, @mrobinson, #41895). Finally, we fixed a panic when selecting nodes in the layout inspector that have no style information (@eerii, #41800).

We’re working towards supporting pausing in the JS debugger (@eerii, @atbrakhi, @jdm, #42007), and breakpoints can be toggled through the UI (@eerii, @atbrakhi, #41925, #42154). While the debugger is paused, hovering over JS objects will report the object’s properties for builtin JS classes (@eerii, @atbrakhi, #42186). Stay tuned for more JS debugging updates in next month’s blog post!

Servo’s WebDriver server is also maturing. Evaluating a synchronous script that returns a Promise will wait until that promise settles (@yezhizhen, #41823). ‘touchmove’ events are fired for pointer actions when a button is pressed (@yezhizhen, #41801), and ‘touchcancel’ events are fired for canceled pointer action items (@yezhizhen, #41937). Finally, any pointer actions that would trigger duplicate ‘mousemove’ events are silently discarded (@mrobinson, #42034).

Element Clear commands now test whether the element is interactable (@yezhizhen, #42124). Now a null script execution timeout value will never trigger a timeout (@yezhizhen, #42184), and synthesized ‘pointermove’ events have a consistent pointerId value (@yezhizhen, #41726).

Embedding

You can now cross-compile Servo using Windows as the host (@yezhizhen, #41748).

We’ve pinned all git dependencies to specific revisions, to reduce the risk of build failures (@Narfinger, #42029). We intend to eventually forbid git dependencies in Servo libraries, which will help unblock releasing Servo on crates.io.

SiteDataManager now has a new clear_site_data() method to clear all stored data for a particular host (@janvarga, #41618, #41709, #41852).

Our nightly testing UI, servoshell, now respects any customized installation path on Windows (@yezhizhen, #41653). We fixed a crash in the Android app when pausing the application (@NiklasMerz, #41827). Additionally, clicking inside a webview in the desktop app will remove focus from any browser UI (@mrobinson, #42080).

We’ve laid more groundwork towards exposing accessibility tree information from webviews (@delan, @lukewarlow, @alice, #41924). There’s nothing to test yet, but keep an eye on our tracking issue if you want to be notified when nightly builds are ready for testing!

Stability & performance

We’ve converted many uses of IPC channels in the engine to channels that are more efficient when multiprocess mode is disabled (@Narfinger, @jdm, @sagudev, @mrobinson, #41178, #41071, #41733, #41806, #41380, #41809, #41774, #42032, #42033, #41412). Since multiprocess mode is not yet enabled by default (--multiprocess), this is a significant boost to Servo’s everyday performance.

Servo now sets a socket timeout for HTTP connections (@Narfinger, @mrobinson, #41710). This is controlled by the network_connection_timeout preference, and defaults to 15 seconds.

Each instance of Servo now starts four fewer threads (@Narfinger, #41740). Any network operations that trigger a synchronous UI operation (such as an HTTP authentication prompt) no longer blocks other network tasks from completing (@Narfinger, @jdm, #41965, #41857).

It’s said that one of the hardest problems in computer science is cache invalidation. We improved the memory usage of dynamic inline SVG content by evicting stale SVG tree data from a cache (@TomRCummings, #41675). Meanwhile, we added a new cache to reduce memory usage and improve rendering performance for pages with animating images (@Narfinger, #41956).

Servo’s JS engine now accounts for 2D and 3D canvas-related memory usage when deciding how often to perform garbage collection (@sagudev, #42180). This can reduce the risk of out-of-memory (OOM) errors on pages that create large numbers of short-lived WebGL or WebGPU objects.

To reduce the risk of panics involving the JS engine integration, we’re continuing to use the Rust type system to make certain kinds of dynamic borrow failures impossible (@sagudev, #41692, #41782, #41756, #41808, #41879, #41878, #41955, #41971, #42123). We also continue to identify and forbid code patterns that can trigger rare crashes when garbage collection happens while destroying webviews (@willypuzzle, #41717, #41783, #41911, #41911, #41977, #41984, #42243).

This month also brought fixes for panics in parallel layout (@mrobinson, #42026), WebGPU (@WaterWhisperer, #42050), <link> fetching (@jdm, #42208), Element.attachShadow() (@mrobinson, #42237), text input methods (@mrobinson, #42240), Web Workers when the developer tools are active (@mrobinson, #42159), IndexedDB (@gterzian, #41960), and asynchronous session history updates (@mrobinson, #42238).

Node.compareDocumentPosition() is now more efficient (@webbeef, #42260), and selections in text inputs no longer require a full page layout (@mrobinson, @Loirooriol, #41963).

Donations

Thanks again for your generous support! We are now receiving 7007 USD/month (−1.4% over December) in recurring donations. This helps us cover the cost of our speedy CI and benchmarking servers, one of our latest Outreachy interns, and funding maintainer work that helps more people contribute to Servo.

Servo is also on thanks.dev, and already 33 GitHub users (+3 over December) that depend on Servo are sponsoring us there. If you use Servo libraries like url, html5ever, selectors, or cssparser, signing up for thanks.dev could be a good way for you (or your employer) to give back to the community.

We now have sponsorship tiers that allow you or your organisation to donate to the Servo project with public acknowlegement of your support. A big thanks from Servo to our newest Bronze Sponsor: str4d! If you’re interested in this kind of sponsorship, please contact us at join@servo.org.

7007 USD/month

10000

Conference talks and blogs

There were two talks about Servo at FOSDEM 2026 (videos and slides here):

Implementing Streams Spec in Servo – Taym Haddadi (@taym95) described the challenges of implementing the Streams Standard.
The Servo project and its impact on the web platform – Manuel Rego (@rego) highlighted the ways that Servo has shaped the web platform and contributed to web standards since it started in 2012.

December in Servo: multiple windows, proxy support, better caching, and more!

2026-01-23T00:00:00Z

Servo 0.0.4 and our December nightly builds now support multiple windows (@mrobinson, @mukilan, #40927, #41235, #41144)! This builds on features that landed in Servo’s embedding API last month. We’ve also landed support for several web platform features, both old and new:

‘contrast-color()’ in CSS color values (@webbeef, #41542)
partial support for <meta charset> (@simonwuelker, #41376)
partial support for encoding sniffing (@simonwuelker, #41435)
‘background’ and ‘bgcolor’ attributes on <table>, <thead>, <tbody>, <tfoot>, <tr>, <td>, <th> (@simonwuelker, #41272)
tee() on readable byte streams (@Taym95, #35991)

For better compatibility with older web content, we now support vendor-prefixed CSS properties like ‘-moz-transform’ (@mrobinson, #41350), as well as window.clientInformation (@Taym95, #41111).

We’ve continued shipping the SubtleCrypto API, with full support for ChaCha20-Poly1305, RSA-OAEP, RSA-PSS, and RSASSA-PKCS1-v1_5 (see below), plus importKey() for ML-KEM (@kkoyung, #41585) and several other improvements (@kkoyung, @PaulTreitel, @danilopedraza, #41180, #41395, #41428, #41442, #41472, #41544, #41563, #41587, #41039, #41292):

Algorithm
ChaCha20-Poly1305	(@kkoyung, #40978, #41003, #41030)
RSA-OAEP	(@kkoyung, @TimvdLippe, @jdm, #41225, #41217, #41240, #41316)
RSA-PSS	(@kkoyung, @jdm, #41157, #41225, #41240, #41287)
RSASSA-PKCS1-v1_5	(@kkoyung, @jdm, #41172, #41225, #41240, #41267)

When using servoshell on Windows, you can now see --help and log output, as long as servoshell was started in a console (@jschwe, #40961).

Servo diagnostics options are now accessible in servoshell via the SERVO_DIAGNOSTICS environment variable (@atbrakhi, #41013), in addition to the usual -Z / --debug= arguments.

Servo’s devtools now partially support the Network > Security tab (@jiang1997, #40567), allowing you to inspect some of the TLS details of your requests. We’ve also made it compatible with Firefox 145 (@eerii, #41087), and use fewer IPC resources (@mrobinson, #41161).

We’ve fixed rendering bugs related to ‘float’, ‘order’, ‘max-width’, ‘max-height’, ‘:link’ selectors, <audio> layout, and getClientRects(), affecting intrinsic sizing (@Loirooriol, #41513), anonymous blocks (@Loirooriol, #41510), incremental layout (@Loirooriol, #40994), flex item sizing (@Loirooriol, #41291), selector matching (@andreubotella, #41478), replaced element layout (@Loirooriol, #41262), and empty fragments (@Loirooriol, #41477).

Servo now fires ‘toggle’ events on <dialog> (@lukewarlow, #40412). We’ve also improved the conformance of ‘wheel’ events (@mrobinson, #41182), ‘hashchange’ events (@Taym95, #41325), ‘dblclick’ events on <input> (@Taym95, #41319), ‘resize’ events on <video> (@tharkum, #40940), ‘seeked’ events on <video> and <audio> (@tharkum, #40981), and the ‘transform’ property in getComputedStyle() (@mrobinson, #41187).

Embedding API

Servo now has basic support for HTTP proxies (@Narfinger, #40941). You can set the proxy URL in the http_proxy (@Narfinger, #41209) or HTTP_PROXY (@treeshateorcs, @yezhizhen, #41268) environment variables, or via --pref network_http_proxy_uri.

We now use the system root certificates by default (@Narfinger, @mrobinson, #40935, #41179), on most platforms. If you don’t want to trust the system root certificates, you can instead continue to use Mozilla’s root certificates with --pref network_use_webpki_roots. As always, you can also add your own root certificates via Opts::certificate_path (--certificate-path=).

We have a new SiteDataManager API for managing localStorage, sessionStorage, and cookies (@janvarga, #41236, #41255, #41378, #41523, #41528), and a new NetworkManager API for managing the cache (@janvarga, @mrobinson, #41255, #41474, #41386). To clear the cache, call NetworkManager::clear_cache, and to list cache entries, call NetworkManager::cache_entries.

Simple dialogs – that is alert(), confirm(), and prompt() – are now exposed to embedders via a new SimpleDialog type in EmbedderControl (@mrobinson, @mukilan, #40982). This new interface is harder to misuse, and no longer requires boilerplate for embedders that wish to ignore simple dialogs.

Web console messages, including messages from the Console API, are now accessible via ServoDelegate::show_console_message and WebViewDelegate::show_console_message (@atbrakhi, #41351).

Servo, the main handle for controlling Servo, is now cloneable for sharing within the same thread (@mukilan, @mrobinson, #41010). To shut down Servo, simply drop the last Servo handle or let it go out of scope. Servo::start_shutting_down and Servo::deinit have been removed (@mukilan, @mrobinson, #41012).

Several interfaces have also been renamed:

Servo::clear_cookies is now SiteDataManager::clear_cookies (@janvarga, #41236, #41255)
DebugOpts::disable_share_style_cache is now Preferences::layout_style_sharing_cache_enabled (@atbrakhi, #40959)
The rest of DebugOpts has been moved to DiagnosticsLogging, and the options have been renamed (@atbrakhi, #40960)

Perf and stability

We can now evict entries from our HTTP cache (@Narfinger, @gterzian, @Taym95, #40613), rather than having it grow forever (or get cleared by an embedder). about:memory now tracks SVG-related memory usage (@d-kraus, #41481), and we’ve fixed memory leaks in <video> and <audio> (@tharkum, #41131).

Servo now does less work when matching selectors (@webbeef, #41368), when focus changes (@mrobinson, @Loirooriol, #40984), and when reflowing boxes whose size did not change (@Loirooriol, @mrobinson, #41160).

To allow for smaller binaries, gamepad support is now optional at build time (@WaterWhisperer, #41451).

We’ve fixed some undefined behaviour around garbage collection (@sagudev, @jdm, @gmorenz, #41546, mozjs#688, mozjs#689, mozjs#692). To better avoid other garbage-collection-related bugs (@sagudev, mozjs#647, mozjs#638), we’ve continued our work on defining (and migrating to) safer interfaces between Servo and the SpiderMonkey GC (@sagudev, #41519, #41536, #41537, #41520, #41564).

We’ve fixed a crash that occurs when <link rel=“shortcut icon”> has an empty ‘href’ attribute, which affected chiptune.com (@webbeef, #41056), and we’ve also fixed crashes in:

‘background-repeat’ (@mrobinson, #41158)
<audio> layout (@Loirooriol, #41262)
custom elements (@mrobinson, #40743)
AudioBuffer (@WaterWhisperer, #41253)
AudioNode (@Taym95, #40954)
ReportingObserver (@Taym95, #41261)
Uint8Array (@jdm, #41228)
the fonts system, on FreeType platforms (@simonwuelker, #40945)
IME usage, on OpenHarmony (@jschwe, #41570)

Donations

Thanks again for your generous support! We are now receiving 7110 USD/month (+10.5% over November) in recurring donations. This helps us cover the cost of our speedy CI and benchmarking servers, one of our latest Outreachy interns, and funding maintainer work that helps more people contribute to Servo.

Servo is also on thanks.dev, and already 30 GitHub users (+2 over November) that depend on Servo are sponsoring us there. If you use Servo libraries like url, html5ever, selectors, or cssparser, signing up for thanks.dev could be a good way for you (or your employer) to give back to the community.

We now have sponsorship tiers that allow you or your organisation to donate to the Servo project with public acknowlegement of your support. A big thanks from Servo to our newest Bronze Sponsors: Anthropy, Niclas Overby, and RxDB! If you’re interested in this kind of sponsorship, please contact us at join@servo.org.

7110 USD/month

10000

Conference talks and blogs

We’ve recently published one talk and one blog post:

Web engine CI on a shoestring budget (slides; transcript) – Delan Azabani (@delan) spoke about the CI system that keeps our builds and tryjobs moving fast, running nearly two million tests in under half an hour.
Servo 2025 Stats – Manuel Rego (@mrego) wrote about the growth of the Servo project, and how our many new contributors have enabled that.

We also have two upcoming talks at FOSDEM 2026 in Brussels later this month:

The Servo project and its impact on the web platform ecosystem – Manuel Rego (@mrego) is speaking on Saturday 31 January at 14:00 local time (13:00 UTC), about Servo’s impact on spec issues, interop bugs, test cases, and the broader web platform ecosystem.
Implementing Streams Spec in Servo web engine – Taym Haddadi (@Taym95) is speaking on Saturday 31 January at 17:45 local time (16:45 UTC), about our experiences writing a new implementation of the Streams API that is independent of the one in SpiderMonkey.

Servo developers Martin Robinson (@mrobinson) and Delan Azabani (@delan) will also be attending FOSDEM 2026, so it would be a great time to come along and chat about Servo!

November in Servo: monthly releases, context menus, parallel CSS parsing, and more!

2025-12-15T00:00:00Z

Landing in Servo 0.0.3 and our November nightly builds, we now have context menus for links, images, and other web content (@atbrakhi, @mrobinson, #40434, #40501), vsync on Android (@mrobinson, #40306), light mode for the new tab page (@arihant2math, #40272), plus several web platform features:

<video controls> (@rayguo17, #40578)
<use> in SVG (@WaterWhisperer, #40684)
☢️ ‘font-optical-sizing’ (@simonwuelker, #40829, #40861, #40884)
‘brotli’ in CompressionStream and DecompressionStream (@Taym95, #40842)
‘display-p3-linear’ in CSS color() and color-mix() (@Loirooriol, #40525)
calc() now works in grid layout (@nicoburns, #34846)
ResizeObserver is now enabled by default (@jdm, #40378)

in SVG,

, and context menus" />

Font variations are now applied in ‘font-weight’ and ‘font-stretch’ (@simonwuelker, #40867), fixing a rendering issue in the Web Engines Hackfest website.

@kkoyung has landed some huge improvements in the SubtleCrypto API, including some of the more modern algorithms in this WICG draft, and a fix for constant-time base64 (@kkoyung, #40334). We now have full support for SHA3-256, SHA3-384, SHA3-512 (@kkoyung, #40765), cSHAKE128, cSHAKE256 (@kkoyung, #40832), Argon2d, Argon2i, Argon2id, ChaCha20-Poly1305, ECDH, ECDSA, and X25519:

Algorithm	deriveBits	exportKey	generateKey	importKey	sign	verify
Argon2d	#40936	n/a	n/a	#40932	n/a	n/a
Argon2i	#40936	n/a	n/a	#40932	n/a	n/a
Argon2id	#40936	n/a	n/a	#40932	n/a	n/a
ChaCha20-Poly1305	n/a	#40948	n/a	#40948	n/a	n/a
ECDH	#40333	#40298	#40305	#40253	n/a	n/a
ECDSA	n/a	#40536	#40553	#40523	#40591	#40557
X25519	#40497	#40421	#40480	#40398	n/a	n/a

<details> now fires ‘toggle’ events (@lukewarlow, #40271), and <details name> is now exclusive, like radio buttons (@simonwuelker, #40314). InputEvent, which represents ‘input’ and ‘beforeinput’ events, now has composed, data, isComposing, and inputType properties (@excitablesnowball, #39989).

Embedding API

Each webview can now now have its own rendering context (@mrobinson, @mukilan, #40794, #40738, #40721, #40594, #40923). This effectively enables full support for multiple windows, and we’ve started incorporating that into servoshell (@mrobinson, @mukilan, #40883).

Our previously unused context menu API has been replaced with a new, more effective API that includes actions for links, images, and other web content (@mrobinson, @atbrakhi, #40402, #40501, #40607). For more details, see the docs for ContextMenu, EmbedderControl::ContextMenu, and WebViewDelegate::show_embedder_control().

WebView now has can_go_back() and can_go_forward() methods, and servoshell now uses those to disable the back and forward buttons (@mrobinson, #40598).

Having introduced our new RefreshDriver API in October, we’ve now removed Servo::animating() (@mrobinson, #40799) and ServoDelegate::notify_animating_changed() (@mrobinson, #40886), and similarly cleaned up the obsolete and inefficient “animating” state in servoshell (@mrobinson, #40715).

We’ve moved virtually all of the useful items in the Servo API to the root of the servo library crate (@mrobinson, #40951). This is a breaking change, but we expect that it will greatly simplify embedding Servo, and it means you can even write use servo::*; in a pinch.

When running Servo without a custom ClipboardDelegate, we normally use the system clipboard by default. But if there’s no system clipboard, we now have a built-in fallback clipboard (@mrobinson, #40408), rather than having no clipboard at all. Note that the fallback clipboard is very limited, as it can only store text and does not work across processes.

Performance and stability

Servo now parses CSS in parallel with script and layout (@mrobinson, @vimpunk, #40639, #40556), and can now measure Largest Contentful Paint in PerformanceObserver as well as in our internal profiling tools (@shubhamg13, @boluochoufeng, #39714, #39384).

Just-in-time compilation (JIT) is now optional (@jschwe, #37972), which can be useful in situations where generating native code is forbidden by policy or unwanted for other reasons.

We’ve improved the performance of incremental layout (@Loirooriol, @mrobinson, #40795, #40797), touch input (@kongbai1996, #40637), animated GIF rendering (@mrobinson, #40158), the prefs subsystem (@webbeef, #40775), and parseFromString() on DOMParser (@webbeef, #40742). We also use fewer IPC resources when internal profiling features are disabled (@lumiscosity, #40823).

We’ve fixed a bug causing nytimes.com to hang (@jdm, #40811), as well as fixing crashes in Speedometer 3.0 and 3.1 (@Narfinger, #40459), grid layout (@nicoburns, #40821), the fonts subsystem (@simonwuelker, #40913), XPath (@simonwuelker, #40411), ReadableStream (@Taym95, #40911), AudioContext (@Taym95, #40729), and when exiting Servo (@mrobinson, #40933).

Donations

Thanks again for your generous support! We are now receiving 6433 USD/month (+11.8% over October) in recurring donations. This helps us cover the cost of our speedy CI and benchmarking servers, one of our latest Outreachy interns, and funding maintainer work that helps more people contribute to Servo.

Servo is also on thanks.dev, and already 28 GitHub users (same as October) that depend on Servo are sponsoring us there. If you use Servo libraries like url, html5ever, selectors, or cssparser, signing up for thanks.dev could be a good way for you (or your employer) to give back to the community.

We now have sponsorship tiers that allow you or your organisation to donate to the Servo project with public acknowlegement of your support. A big thanks from Servo to our newest Bronze Sponsors: Jenny & Phil Porada, Josh Aas, LambdaTest, and Sandwich! If you’re interested in this kind of sponsorship, please contact us at join@servo.org.

6433 USD/month

10000

Servo Sponsorship Tiers

2025-11-21T00:00:00Z

The Servo project is happy to announce the following new sponsorship tiers to encourage more donations to the project:

Platinum: 10,000 USD/month
Gold: 5,000 USD/month
Silver: 1,000 USD/month
Bronze: 100 USD/month

Organizations and individual sponsors donating in these tiers will be acknowledged on the servo.org homepage with their logo or name. Please note that such donations should come with no obligations to the project i.e they should be “no strings attached” donations. All the information about these new tiers is available at the Sponsorship page on this website.

Please contact us at join@servo.org if you are interested in sponsoring the project through one of these tiers.

Use of donations is decided transparently via the Technical Steering Committee’s public funding request process, and active proposals are tracked in servo/project#187.

Last, but not least, we’re excited to welcome our first bronze sponsor LambdaTest who has recently started donating to the Servo project. Thank you very much!

October in Servo: better for the web, better for embedders, better for you

2025-11-14T00:00:00Z

Servo now supports several new web platform features:

<source> in <video> and <audio> (@tharkum, #39717)
CompressionStream and DecompressionStream (@kkoyung, #39658)
fetchLater() (@TimvdLippe, #39547)
Document.parseHTMLUnsafe() (@lukewarlow, #40246)
the which property on UIEvent (@Taym95, #40109)
the relatedTarget property on UIEvent (@TimvdLippe, #40182)
self.name and .onmessageerror in dedicated workers (@yerke, #40156)
name and areas properties on HTMLMapElement (@tharkum, #40133)

servoshell for macOS now ships as native Apple Silicon binaries (@jschwe, #39981). Building servoshell for macOS x86-64 still works for now, but is no longer officially supported by automated testing in CI (see § For developers).

In servoshell for Android, you can now enable experimental mode with just two taps (@jdm, #40054), use the software keyboard (@jdm, #40009), deliver touch events to web content (@mrobinson, #40240), and dismiss the location field (@jdm, #40049). Pinch zoom is now fully supported in both Servo and servoshell, taking into account the locations of pinch inputs (@mrobinson, @atbrakhi, #40083) and allowing keyboard scrolling when zoomed in (@mrobinson, @atbrakhi, #40108).

servoshell on Android showing GitHub loaded with an internal error, then enabling experimental mode in the settings menu, then reloading the page successfully (click to pause)

▶

servoshell on Android showing a page that opens the software keyboard and listens for touch events (click to pause)

▶

servoshell on Android. Left: you can now turn on experimental mode in the settings menu. Right: we now support the soft keyboard and touch events.

AbortController and AbortSignal are now enabled by default (@jdm, @TimvdLippe, #40079, #39943), after implementing AbortSignal.timeout() (@Taym95, #40032) and fixing throwIfAborted() on AbortSignal (@Taym95, #40224). If this is the first time you’ve heard of them, you might be surprised how important they are for real-world web compat! Over 40% of Google Chrome page loads at least check if they are supported, and many popular websites including GitHub and Discord are broken without them.

XPath is now enabled by default (@simonwuelker, #40212), after implementing ‘@attr/parent’ queries (@simonwuelker, #39749), Copy > XPath in the DevTools Inspector (@simonwuelker, #39892), completely rewriting the parser (@simonwuelker, #39977), and landing several other fixes (@simonwuelker, #40103, #40105, #40161, #40167, #39751, #39764).

Servo now supports new KeyboardEvent({keyCode}) and ({charCode}) (@atbrakhi, #39590), which is enough to get Speedometer 3.0 and 3.1 working on macOS.

ImageData can now be sent over postMessage() and structuredClone() (@Gae24, #40084).

Layout engine

Our layout engine can now render text in synthetic bold (@minghuaw, @mrobinson, #39519, #39681, #39633, #39691, #39713), and now selects more appropriate fallback fonts for Kanji in Japanese text (@arayaryoma, #39608).

‘initial-scale’ now does the right thing in <meta name=viewport> (@atbrakhi, @shubhamg13, @mrobinson, #40055).

We’ve improved the way we handle ‘border-radius’ (@Loirooriol, #39571) and margin collapsing (@Loirooriol, #36322). While they’re fairly unassuming fixes on the surface, both of them allowed us to find interop issues in the big incumbent engines (@Loirooriol, #39540, #36321) and help improve web standards (@noamr, @Loirooriol, csswg-drafts#12961, csswg-drafts#12218).

In other words, Servo is good for the web, even if you’re not using it yet!

Embedding and ecosystem

Our HTML-compatible XPath implementation now lives in its own crate, and it’s no longer limited to the Servo DOM (@simonwuelker, #39546). We don’t have any specific plans to release this as a standalone library just yet, but please let us know if you have a use case that would benefit from this!

You can now take screenshots of webviews with WebView::take_screenshot (@mrobinson, @delan, #39583).

Historically Servo has struggled with situations causing 100% CPU usage or unnecessary work on every tick of the event loop, whenever a page is considered “active” or “animating” (#25305, #3406). We had since throttled animations (@mrobinson, #37169) and reflows (@mrobinson, @Loirooriol, #38431), but only to fixed rates of 120 Hz and 60 Hz respectively.

But starting this month, you can run Servo with vsync, thanks to the RefreshDriver trait (@coding-joedow, @mrobinson, #39072), which allows embedders to tell Servo when to start rendering each frame. The default driver continues to run at 120 Hz, but you can define and install your own with ServoBuilder::refresh_driver.

Breaking changes

Servo’s embedding API has had a few breaking changes:

Opts::wait_for_stable_image was removed; to wait for a stable image, call WebView::take_screenshot instead (@mrobinson, @delan, #39583).
MouseButtonAction::Click was removed; use Down followed by Up. Click events need to be derived from mouse button downs and ups to ensure that they are fired correctly (@mrobinson, #39705).
Scrolling is now derived from mouse wheel events. When you have mouse wheel input to forward to Servo, you should now call WebView::notify_input_event only, not notify_scroll_event (@mrobinson, @atbrakhi, #40269).
WebView::set_pinch_zoom was renamed to pinch_zoom, to better reflect that pinch zoom is always relative (@mrobinson, @atbrakhi, #39868).

We’ve improved page zoom in our webview API (@atbrakhi, @mrobinson, @shubhamg13, #39738), which includes some breaking changes:

WebView::set_zoom was renamed to set_page_zoom, and it now takes an absolute zoom value. This makes it idempotent, but it means if you want relative zoom, you’ll have to multiply the zoom values yourself.
Use the new WebView::page_zoom method to get the current zoom value.
WebView::reset_zoom was removed; use set_page_zoom(1.0) instead.

Some breaking changes were also needed to give embedders a more powerful way to share input events with webviews (@mrobinson, #39720). Often both your app and the pages in your webviews may be interested in knowing when users press a key. Servo handles these situations by asking the embedder for all potentially useful input events, then echoing some of them back:

Embedder calls WebView::notify_input_event to tell Servo about an input event, then web content (and Servo) can handle the event.
Servo calls WebViewDelegate::notify_keyboard_event to tell the embedder about keyboard events that were neither canceled by scripts nor handled by Servo itself. The event details is included in the arguments.

Embedders had no way of knowing when non-keyboard input events, or keyboard events that were canceled or handled by Servo, have completed all of their effects in Servo. This was good enough for servoshell’s overridable key bindings, but not for WebDriver, where commands like Perform Actions need to reliably wait for input events to be handled. To solve these problems, we’ve replaced notify_keyboard_event with notify_input_event_handled:

Embedder calls WebView::notify_input_event to tell Servo about an input event, then web content (and Servo) can handle the event. This now returns an InputEventId, allowing embedders to remember input events that they still care about for step 2.
Servo calls WebViewDelegate::notify_input_event_handled to tell the embedder about every input event, when Servo has finished handling it. The event details are not included in the arguments, but you can use the InputEventId to look up the details in the embedder.

Perf and stability

Servo now does zero unnecessary layout work when updating canvases and animated images, thanks to a new “UpdatedImageData” layout mode (@mrobinson, @mukilan, #38991).

We’ve fixed crashes when clicking on web content on Android (@mrobinson, #39771), and when running Servo on platforms where JIT is forbidden (@jschwe, @sagudev, #40071, #40130).

For developers

CI builds for pull requests should now take 70% less time, since they now run on self-hosted CI runners (@delan, #39900, #39915). Bencher builds for runtime benchmarking now run on our new dedicated servers, so our Speedometer and Dromaeo data should now be more accurate and less noisy (@delan, #39272).

We’ve now switched all of our macOS builds to run on arm64 (@sagudev, @jschwe, #38460, #39968). This helps back our macOS releases with thorough automated testing on the same architecture as our releases, but we can’t run them on self-hosted CI runners yet, so they may be slower for the time being.

Work is underway to set up faster macOS arm64 runners on our own servers (@delan, ci-runners#64), funded by your donations. Speaking of which!

Donations

Thanks again for your generous support! We are now receiving 5753 USD/month (+1.7% over September) in recurring donations.

This helps us cover the cost of our speedy CI and benchmarking servers, one of our latest Outreachy interns, and funding maintainer work that helps more people contribute to Servo. Keep an eye out for further CI improvements in the coming months, including faster macOS arm64 builds and ten-minute WPT builds.

Servo is also on thanks.dev, and already 28 GitHub users (same as September) that depend on Servo are sponsoring us there. If you use Servo libraries like url, html5ever, selectors, or cssparser, signing up for thanks.dev could be a good way for you (or your employer) to give back to the community.

5753 USD/month

10000

This month in Servo: experimental mode, Trusted Types, strokeText(), and more!

2025-10-24T00:00:00Z

September was another busy month for Servo, with a bunch of new features landing in our nightly builds:

the Trusted Types API is now stable (@TimvdLippe, #39281, #39263)
strokeText() on CanvasRenderingContext2D (@sagudev, #39183)
invertSelf() on DOMMatrix (@lumiscosity, #39148)
getType() and supports() on ClipboardItem (@Gae24, #39296)
getAll() and getAllKeys() on IDBObjectStore (@arihant2math, #38885)
scrollParent property on HTMLElement (@mrobinson, @Loirooriol, #39110)
sizes property on HTMLImageElement (@tharkum, #39466)

servoshell now has a new experimental mode button (☢). Turning on experimental mode has the same effect as running Servo with --enable-experimental-web-platform-features: it enables all engine features, even those that may not be stable or complete. This works much like Chromium’s option with the same name, and it can be useful when a page is not functioning correctly, since it may allow the page to make further progress.

Top to bottom: experimental mode off, experimental mode on.

Viewport meta tags are now enabled on mobile devices only, fixing a bug where they were enabled on desktop (@shubhamg13, #39133). You can still enable them if needed with --pref viewport_meta_enabled (@shubhamg13, #39207).

Servo now supports ‘Content-Encoding: zstd’ (@webbeef, #36530), and we’ve fixed a bug causing spurious credentials prompts when a HTTP 401 has no ‘WWW-Authenticate’ header (@simonwuelker, #39215). We’ve also made a bunch of progress on AbortController (@TimvdLippe, #39290, #39295, #39374, #39406) and <link rel=preload> (@TimvdLippe, @jdm, #39033, #39034, #39052, #39146, #39167).

‘Content-Security-Policy: sandbox’ now disables scripting unless ‘allow-scripts’ is given (@TimvdLippe, #39163), and crypto.subtle.exportKey() can now export HMAC keys in raw format (@arihant2math, #39059).

The scrollIntoView() method on Element now works with shadow DOM (@mrobinson, @Loirooriol, #39144), and recurses to parent iframes if they are same origin (@Loirooriol, @mrobinson, #39475, #39397, #39153).

Several types of DOM exceptions can now have error messages (@arihant2math, @rodio, @excitablesnowball, #39056, #39394, #39535), and we’ve also fixed a bug where links often need to be clicked twice (@yezhizhen, #39326), and fixed bugs affecting <img> attribute changes (@tharkum, #39483), the ‘:defined’ selector (@mukilan, #39325, #39390), invertSelf() on DOMMatrix (@lumiscosity, #39113), and the ‘href’ setter on Location (@arihant2math, @sagudev, #39051).

One complex part of Servo isn’t even written in Rust, it’s written in Python! codegen.py, which describes how to generate Rust code with bindings for every known DOM interface from the WebIDL, is now fully type annotated (@jerensl, @mukilan, #39070, #38998).

Embedding and automation

Servo now requires Rust 1.86 to build (@sagudev, #39185).

Keyboard scrolling is now automatically implemented by Servo (@delan, @mrobinson, #39371, #39469), so embedders no longer need to translate arrow keys, Home, End, Page Up, and Page Down to WebView API calls. This change also improves the behaviour of those keys, scrolling the element or <iframe> that was focused or most recently clicked (or a nearby ancestor).

DebugOptions::convert_mouse_to_touch (-Z convert-mouse-to-touch) has been removed (@mrobinson, #39352), with no replacement. Touch event simulation continues to be available in servoshell as --simulate-touch-events.

DebugOptions::webrender_stats (-Z wr-stats in servoshell) has been removed (@mrobinson, #39331); instead call toggle_webrender_debugging(Profiler) on a WebView (or press Ctrl+F12 in servoshell).

DebugOptions::trace_layout (-Z trace-layout) has been removed (@mrobinson, #39332), since it had no effect.

We’ve improved the docs for WebViewDelegate::notify_history_changed (@Narfinger, @mrobinson, @yezhizhen, #39134).

When automating servoshell with WebDriver, commands targeting elements now correctly scroll into view if needed (@PotatoCP, @yezhizhen, #38508, #39265), allowing Element Click, Element Send Keys, Element Clear, and Take Element Screenshot to work properly when the element is outside the viewport.

WebDriver mouse inputs now work correctly with HiDPI scaling on more platforms (@mrobinson, #39472), and we’ve improved the reliability of Take Screenshot, Take Element Screenshot (@yezhizhen, #39499, #39539, #39543), Switch To Frame (@yezhizhen, #39086), Switch To Window (@yezhizhen, #39241), and New Session (@yezhizhen, #39040).

These improvements have enabled us to run the WebDriver conformance tests in CI by default (@PotatoCP, #39087), and also mean we’re closer than ever to running WebDriver-based Web Platform Tests.

servoshell

Favicons now update correctly when you navigate back and forward (@webbeef, #39575), not just when you load a new page.

servoshell’s command line argument parsing has been reworked (@Narfinger, #37194, #39316), which should fix the confusing behaviour of some options.

On mobile devices, servoshell now resizes the webview correctly when the available space changes (@blueguy1, @yjx, @yezhizhen, #39507).

On macOS, telling servoshell to take a screenshot no longer hides the window (@mrobinson, #39500). This does not affect taking a screenshot in headless mode (--headless), where there continues to be no window at all.

Performance

Servo currently runs in single-process mode unless you opt in to --multiprocess mode, and we’ve landed a few perf improvements in that default mode. For one, in single-process mode, script can now communicate with the embedder directly for reduced latency (@jschwe, #39039). We also create one thread pool for the image cache now, rather than one pool per origin (@rodio, #38783).

Many components of Servo that would be separated by a process boundary in multiprocess mode, now use crossbeam channels in single-process mode, rather than using IPC channels in both modes (@jschwe, #39073, #39076, #39345, #39347, #39348, #39074). IPC channels are required when communicating with another process, but they’re more expensive, because they require serialising and deserialising each message, plus resources from the operating system.

We’ve started working on an optimisation for string handling in Servo’s DOM layer (@Narfinger, #39480, #39481, #39504). Strings in our DOM have historically been represented as ordinary Rust strings, but they often come from SpiderMonkey, where they use a variety of representations, none of which are entirely compatible. SpiderMonkey strings would continue to need conversion to Servo strings, but the idea we’re working towards is to make the conversion lazy, in the hope that many strings will never end up being converted at all.

We now use a faster hash algorithm for internal hashmaps that are not security-critical (@Narfinger, #39106, #39166, #39202, #39233, #39244, #39168). These changes also switch that faster algorithm from FNV to an even simpler polynomial hash, following in the footsteps of Rust and Stylo.

We’ve also landed a few more self-contained perf improvements:

speeding up accesses to the event loop (@Narfinger, #39274, #39275)
avoviding new display lists while loading CSS images (@coding-joedow, #39201)
reducing memory usage (@ritoban23, #39351)
reducing binary size (@lumiscosity, @Narfinger, #39437, #39567)

Donations

Thanks again for your generous support! We are now receiving 5654 USD/month (+1.8% over August) in recurring donations.

Servo is also on thanks.dev, and already 28 GitHub users (±13 from August) that depend on Servo are sponsoring us there. If you use Servo libraries like url, html5ever, selectors, or cssparser, signing up for thanks.dev could be a good way for you (or your employer) to give back to the community.

5654 USD/month

10000

Conference talks

MiniApps Design and Servo (starting at ~2:37:00; slides) — Gregory Terzian (@gterzian) spoke about how Servo can be used as a web engine for mini-app platforms at WebEvolve 2025

独⽴的，轻量级，模块化与并⾏处理架构的Web引擎开发 [zh] / Developing an independent, light-weight, modular and parallel web-engine [en] (starting at ~5:49:00; slides) — Jonathan Schwender (@jschwe) spoke about Servo’s goals and status at WebEvolve 2025

Servo: A new web engine written in Rust* (slides; transcript) — Manuel Rego (@rego) spoke about the Servo project at GOSIM Hangzhou 2025

Driving Innovation with Servo and OpenHarmony: Unified Rendering and WebDriver* (slides) — Jingshi Shangguan & Zhizhen Ye (@yezhizhen) spoke about a new OpenHarmony rendering backend and WebDriver support in Servo at GOSIM Hangzhou 2025

The Joy and Value of Embedded Servo Systems* (slides) — Gregory Terzian (@gterzian) spoke about embedding Servo at GOSIM Hangzhou 2025

A Dive Into the Servo Layout System* (slides) — Martin Robinson (@mrobinson) & Oriol Brufau (@obrufau) spoke about the architecture of Servo’s parallel and incremental layout system at GOSIM Hangzhou 2025

* video coming soon; go to our About page for updates

Servo 0.0.1 Release

2025-10-20T00:00:00Z

Today, the Servo team has released new versions of the servoshell binaries for all our supported platforms, tagged v0.0.1. These binaries are essentially the same nightly builds that were already available from the download page with additional manual testing, now tagging them explicitly as releases for future reference.

We plan to publish such a tagged release every month. For now, we are adopting a simple release process where we will use a recent nightly build and perform additional manual testing to identify issues and regressions before tagging and publishing the binaries.

There are currently no plans to publish these releases on crates.io or platform-specific app stores. The goal is just to publish tagged releases on GitHub.

This month in Servo: variable fonts, network tools, SVG, and more!

2025-09-25T00:00:00Z

Another month, another record number of pull requests merged! August flew by, and with it came 447 pull requests from Servo contributors. It was also the final month of our Outreachy cohort; you can read Jerens’ and Uthman’s blogs to learn about how it went!

Highlights

Our big new feature this month is rendering inline SVG elements (@mukilan, @Loirooriol, #38188, #38603). This improves the appearance of many popular websites.

Did you know that the Google logo is an SVG element?

We have implemented named grid line lines and areas (@nicoburns, @loirooriol, #38306, #38574, #38493), still gated behind the layout_grid_enabled preference (#38306, #38574).

CSS grids are all around us.

Servo now supports CSS ‘font-variation-settings’ on all main desktop platforms (@simonwuelker, @mrobinson, #38642, #38760, #38831). This feature is currently gated behind the layout_variable_fonts_enabled preference. We also respect format(*-variations) inside @font-face rules (@mrobinson, #38832). Additionally, Servo now reads data from OpenType Collection (.ttc) system font files on macOS (@nicoburns, #38753), and uses Helvetica for the ‘system-ui’ font (@dpogue, #39001).

▶

This font can be customized!

Our developer tools continue to make progress! We now have a functional network monitor panel (@uthmaniv, @jdm, #38216, #38601, #38625), and our JS debugger can show potential breakpoints (@delan, @atbrakhi, #38331, #38363, #38333, #38551, #38550, #38334, #38624, #38826, #38797). Additionally, the layout inspector now dims nodes that are not displayed (@simonwuelker, #38575).

That's a lot of network requests.

We’ve fixed a significant source of crashes in the engine: hit testing using outdated display lists (issue #37932). Hit testing in a web rendering engine is the process that determines which element(s) the user’s mouse is hovering over.

Previously, this process ran inside of WebRender, which receives a display list representing what should be rendered for a particular page. WebRender runs on a separate thread or process from the actual page content, so display lists are updated asynchronously. By the time we do a hit test, the elements reported may not exist anymore, so we could trigger crashes by (for example) moving the mouse quickly over parts of the page that were rapidly changing.

This was fixed by making the hit test operation synchronous and moving it into the same thread as the actual content being tested against, eliminating the possibility of outdated results (@mrobinson, @Loirooriol, @kongbai1996, @yezhizhen, #38480, #38464, #38463, #38884, #38518).

Web platform support

DOM & JS

We’ve upgraded to SpiderMonkey v140 (changelog) (@jdm, #37077, #38563).

Numerous pieces of the Trusted Types API are now present in Servo (@TimvdLippe, @jdm, #38595, #37834, #38700, #38736, #38718, #38784, #38871, #8623, #38874, #38872, #38886), all gated behind the dom_trusted_types_enabled preference.

The IndexedDB implementation (gated behind dom_indexeddb_enabled) is progressing quickly (@arihant2math, @jdm, @rodion, @kkoyung, #28744, #38737, #38836, #38813, #38819, #38115, #38944, #38740, #38891, #38723, #38850, #38735), now reporting errors via IDBRequest interface and supporting autoincrement keys.

A prototype implementation of the CookieStore API is now implemented and gated by the dom_cookiestore_enabled preference (@sebsebmc, #37968, #38876).

Servo now passes over 99.6% of the CSS geometry test suite, thanks to an implementation of matrixTransform() on DOMPointReadOnly, making all geometry interfaces serializable, and adding the SVGMatrix and SVGPoint aliases (@lumiscosity, #38801, #38828, #38810).

You can now use the TextEncoderStream API (@minghuaw, #38466). Streams that are piped now correctly pass through undefined values, too (@gterzian, #38470). We also fixed a crash in the result of pipeTo() on ReadableStream (@gterzian, #38385).

We’ve implemented getModifierState() on MouseEvent (@PotatoCP, #38535), and made a number of changes involving DOM events: ‘mouseleave’ events are fired when the pointer leaves an <iframe> (@mrobinson, @Loirooriol, #38539), pasting from the clipboard into a text input triggers an ‘input’ event (@mrobinson, #37100), focus now occurs after ‘mousedown’ instead of ‘click’ (@yezhizhen, #38589), we ignore ‘mousedown’ and ‘mouseup’ events for elements that are disabled (@yezhizhen, #38671), and removing an event handler attribute like ‘onclick’ clears all relevant event listeners (@TimvdLippe, @kotx, #38734, #39011).

Servo now supports scrollIntoView() (@abdelrahman1234567, #38230), and fires a ‘scroll’ event whenever a page is scrolled (@stevennovaryo, #38321). You can now focus an element without scrolling, by passing the {preventScroll: true} option to focus() (@abdelrahman1234567, #38495).

navigator.sendBeacon() is now implemented, gated behind the dom_navigator_sendbeacon_enabled preference (@TimvdLippe, #38301). Similarly, the AbortSignal.abort() static method is hidden behind dom_abort_controller_enabled (@Taym95, #38746).

The HTMLDocument interface now exists as a property on the Window object (@leo030303, #38433). Meanwhile, the CSS window property is now a WebIDL namespace (@simonwuelker, #38579). We also implemented the new QuotaExceededError interface (@rmeno12, #38507, #38720), which replaces previous usages of DOMException with the QUOTA_EXCEEDED_ERR name.

Our 2D canvas implementation now supports addPath() on Path2D (@arthmis, #37838) and the restore() methods on CanvasRenderingContext2D and OffscreenCanvas now pop all applied clipping paths (@sagudev, #38496). Additionally, we now support using web fonts in the 2D canvas (@mrobinson, #38979). Meanwhile, the performance continues to improve in the new Vello-based backends (@sagudev, #38406, #38356, #38440, #38437), with asynchronous uploading also showing improvements (@sagudev, @mrobinson, #37776).

Muting media elements with the ‘mute’ HTML attribute now works during the initial resource load (@rayguo17, @jschwe, #38462).

Modifying stylesheets now integrates better with incremental layout, in both light trees and shadow trees (@coding-joedow, #38530, #38529). Note that calling setProperty() on a readonly CSSStyleDeclaration correctly throws an exception (@simonwuelker, #38677).

CSS

We’ve upgraded to the upstream Stylo revision as of August 1, 2025.

We now support custom CSS properties with the CSS.registerProperty() method (@simonwuelker, #38682), as well as custom element states with the ‘states’ property on ElementInternals (@simonwuelker, #38564).

Flexbox cross sizes can no longer end up negative through stretching (@Loirooriol, #38521), while ‘stretch’ on flex items now stretches to the line if possible (@Loirooriol, #38526).

Overflow calculations are more accurate, now that we ignore ‘position: fixed’ children of the root element (@stevennovaryo, #38618), compute overflow for <body> separate from the viewport (@shubhamg13, #38825), check for ‘overflow: visible’ in parents and children (@shubhamg13, #38443), and propagate ‘overflow’ to the viewport correctly (@shubhamg13, @Loirooriol, #38598).

‘color’ and ‘text-decoration’ properties no longer inherit into the contents of <select> elements (@simonwuelker, #38570).

Negative outline offsets work correctly (@lumiscosity, @mrobinson, #38418).

Video elements no longer fall back to a preferred aspect ratio of 2 (@Loirooriol, #38705).

‘position: sticky’ elements are handled correctly inside CSS transforms (@mrobinson, @Loirooriol, #38391).

Performance & Stability

We fixed several panics this month, involving IntersectionObserver and missing stacking contexts (@mrobinson, #38473), unpaintable canvases and text (@gterzian, #38664), serializing ‘location’ properties on Window objects (@jdm, #38709), and navigations canceled before HTTP headers are received (@gterzian, #38739).

We also fixed a number of performance pitfalls. The document rendering loop is now throttled to 60 FPS (@mrobinson, @Loirooriol, #38431), while animated images do less work when advancing the current frame (@mrobinson, #38857). In addition, elements with CSS images will not trigger page reflow until their image data is fully available (@coding-joedow, #38916).

Finally, we made improvements to memory usage and binary size. Inline stylesheets are now deduplicated, which can have a significant impact on pages with lots of form inputs or custom elements with common styles (@coding-joedow, #38540). We also removed many unused pieces of the ICU library, saving 16MB from the final binary.

Embedding

Servo has declared a Minimum Supported Rust Version (1.85.0), and this is verified with every new pull request (@jschwe, #37152).

Evaluating JS from the embedding layer now reports an error if the evaluation failed for any reason (@rodio, #38602).

Our WebDriver implementation now passes 80% of the implementation conformance tests. This is the result of lots of work on handling user prompts (@PotatoCP, #38591), computing obscured/disabled elements while clicking (@yezhizhen, #38497, #38841, #38436, #38490, #38383), and improving window focus behaviours (@yezhizhen, #38889, #38909). We also implemented the Get Window Handles command (@longvatrong111, @yezhizhen, #38622, #38745), added support for getting element boolean attributes (@kkoyung, #38401), and added more accurate errors for a number of commands (@yezhizhen, @longvatrong111, #38620, #38357). The Element Clear command now clears <input type="file"> elements correctly (@PotatoCP, #38536), and Element Send Keys now appends to file inputs with the ‘multiple’ attribute.

servoshell

We now display favicons of each top-level page in the tab bar (@simonwuelker, #36680).

Resizing the browser window to a very small dimension no longer crashes the browser (@leo030303, #38461). Element hit testing in full screen mode now works as expected (@yezhizhen, #38328).

Various popup dialogs, such as the <select> option chooser dialog, can now be closed without choosing a value (@TimvdLippe, #38373, #38949). Additionally, the browser now responds to a popup closing without any other inputs (@lumiscosity, #39038).

Donations

Thanks again for your generous support! We are now receiving 5552 USD/month (+18.3% over July) in recurring donations.

Historically this has helped cover the cost of our speedy CI servers and Outreachy interns. Thanks to your support, we’re now setting up two new CI servers for benchmarking, and funding the work of our long-time maintainer Josh Matthews (@jdm), with a particular focus on helping more people contribute to Servo.

Keep an eye out for further CI improvements in the coming months, including ten-minute WPT builds, macOS arm64 builds, and faster pull request checks.

Servo is also on thanks.dev, and already 15 GitHub users (−7 from July) that depend on Servo are sponsoring us there. If you use Servo libraries like url, html5ever, selectors, or cssparser, signing up for thanks.dev could be a good way for you (or your employer) to give back to the community.

5552 USD/month

10000

As always, use of these funds will be decided transparently in the Technical Steering Committee. For more details, head to our Sponsorship page.