Thanks for adding that feedback! LGTM3 On Fri, Jan 23, 2026 at 12:35 PM 'Stephen White' via blink-dev < [email protected]> wrote:
> Hi Alex, > > I've added a statement from Unity to the "Web / Framework developer views > notes". Unity is an important partner, so this carries some weight. We will > add more if/when it comes in. > > Stephen > > On Wed, Jan 14, 2026 at 11:05 AM Alex Russell <[email protected]> > wrote: > >> It's a little odd that there's no developer feedback here. Is it correct >> that we're shipping first? And is there a list of features that will not be >> available in this mode? Does it unlock software rendering? >> >> Thanks, >> >> Alex >> >> On Wednesday, January 14, 2026 at 6:22:11 AM UTC-8 Stephen White wrote: >> >>> Sure! The above proposal was converted into spec text on a feature >>> branch. This >>> <https://github.com/gpuweb/gpuweb/commit/6eae31ebb74b4877d91ddce47865ba89bf1ae1a5> >>> is >>> the merge commit that brought those changes into the main spec. The changes >>> are not isolated to a single section, but each restriction appears in a >>> cyan box labelled "Compatibility Mode", easiest to find by searching for >>> "core-features-and-limits". >>> >>> These are the (largely minor) followup changes that landed after that >>> merge: >>> >>> - Disallow cube-array in createTexture >>> >>> <https://github.com/gpuweb/gpuweb/commit/f34e4301de148b82936737bf7312c0a496b6e7e2> >>> - Fix maxStorageTexturesIn*Stage defaults >>> >>> <https://github.com/gpuweb/gpuweb/commit/78dfad2eb1c8dcbd00430562e147eb3a052a5e3e> >>> - [editorial] Tweak requestAdapter step ordering, feature level >>> definitions (again) >>> >>> <https://github.com/gpuweb/gpuweb/commit/b984d18e327a5691dfdf7cc2b8746972552e2c54> >>> >>> Stephen >>> >>> On Wed, Jan 14, 2026 at 8:48 AM Yoav Weiss (@Shopify) < >>> [email protected]> wrote: >>> >>>> >>>> >>>> On Tuesday, January 13, 2026 at 9:16:24 PM UTC+1 Chromestatus wrote: >>>> >>>> *Contact emails* >>>> [email protected], [email protected] >>>> >>>> *Explainer* >>>> https://github.com/explainers-by-googlers/webgpu- >>>> compatibility-mode/blob/main/README.md >>>> >>>> *Specification* >>>> https://github.com/gpuweb/gpuweb/blob/main/proposals/ >>>> compatibility-mode.md >>>> >>>> >>>> Can you point to a PR or a spec section that includes the change? >>>> >>>> >>>> >>>> >>>> *Summary* >>>> Adds an opt-in, lightly restricted subset of the WebGPU API capable of >>>> running older graphics APIs such as OpenGL and Direct3D11. By opting into >>>> this mode and obeying its constraints, developers can extend the reach of >>>> their WebGPU applications to many older devices that do not have the >>>> modern, explicit graphics APIs that core WebGPU requires. For simple >>>> applications, the only required change is to specify the "compatibility" >>>> featureLevel when calling requestAdapter. For more advanced applications, >>>> some modifications may be necessary to accommodate the mode's restrictions. >>>> Since Compatibility mode is a subset, the resulting applications are also >>>> valid WebGPU Core applications and will run even on user agents that do not >>>> support Compatibility mode. >>>> >>>> *Blink component* >>>> Blink>WebGPU >>>> <https://issues.chromium.org/issues?q=customfield1222907:%22Blink%3EWebGPU%22> >>>> >>>> *Web Feature ID* >>>> webgpu <https://webstatus.dev/features/webgpu> >>>> >>>> *Motivation* >>>> WebGPU is a good match for modern graphics APIs such as Vulkan, Metal >>>> and Direct3D 12. However, there are a large number of devices which do not >>>> yet support those APIs. In particular, on Chrome on Windows, 31% of Chrome >>>> users do not have Direct3D FL 11.1 or higher. On Android, 23% of Android >>>> users do not have Vulkan 1.1, including 15% who do not have Vulkan at all ( >>>> https://developer.android.com/about/dashboards). On ChromeOS, Vulkan >>>> penetration is still quite low, while OpenGL ES 3.1 is ubiquitous. >>>> Developers are thus forced to write multiple implementations (e.g., WebGPU >>>> and WebGL) for maximum reach, to accept the reduced reach that core WebGPU >>>> currently provides, or to write only for WebGL and forgo the advanced >>>> features of WebGPU, such as GPU compute. By opting in to Compatibility >>>> Mode, developers can target a wider reach of devices with a single >>>> implementation. >>>> >>>> *Initial public proposal* >>>> https://github.com/gpuweb/gpuweb/blob/main/proposals/ >>>> compatibility-mode.md >>>> >>>> *TAG review* >>>> https://github.com/w3ctag/design-reviews/issues/1063 >>>> >>>> *TAG review status* >>>> Issues addressed >>>> >>>> *Origin Trial Name* >>>> WebGPU Compatibility Mode >>>> >>>> *Chromium Trial Name* >>>> WebGPUCompatibilityMode >>>> >>>> *Origin Trial documentation link* >>>> https://github.com/explainers-by-googlers/webgpu- >>>> compatibility-mode/blob/main/README.md >>>> >>>> *WebFeature UseCounter name* >>>> kWebGPUFeatureLevelCompatibility >>>> >>>> *Risks* >>>> >>>> >>>> *Interoperability and Compatibility* >>>> This feature has been approved in W3C GPU for the Web WG meetings >>>> including participants from Safari and Firefox. >>>> >>>> *Gecko*: Positive Although there is not currently an entry for >>>> Compatibility Mode in the standards positions repos, WebGPU Compatibility >>>> Mode was discussed and approved by Google, Apple and Mozilla in the GPU for >>>> the Web Working Group, and has the same support as WebGPU Core. Each of the >>>> commits to the compatibility-mode propsal above was approved by a working >>>> group member from each of those three organizations, and any disagreements >>>> were resolved prior to landing in Working Group meetings. >>>> >>>> *WebKit*: Positive Although there is not currently an entry for >>>> Compatibility Mode in the standards positions repos, WebGPU Compatibility >>>> Mode was discussed and approved by Google, Apple and Mozilla in the GPU for >>>> the Web Working Group, and has the same support as WebGPU Core. Each of the >>>> commits to the compatibility-mode propsal above was approved by a working >>>> group member from each of those three organizations, and any disagreements >>>> were resolved prior to landing in Working Group meetings. >>>> >>>> *Web developers*: No signals >>>> >>>> *Other signals*: >>>> >>>> *Security* >>>> Being a lightly-restricted subset, Compatibility Mode does not >>>> introduce any accessibility, security, or privacy issues over and above >>>> those introduced by core WebGPU. For this reason, the security review >>>> submitted for WebGPU also applies to Compatibility Mode. >>>> >>>> *WebView application risks* >>>> >>>> Does this intent deprecate or change behavior of existing APIs, such >>>> that it has potentially high risk for Android WebView-based applications? >>>> Low; does not remove or alter existing APIs. Provides a >>>> lightly-restricted subset of the WebGPU API to older devices which are not >>>> capable of the core WebGPU API In case of emergency, there are two >>>> independent killswitches: - kWebGPUAndroidOpenGLES controls the Dawn >>>> OpenGLES backend on Android in the GPU process - RuntimeEnabledFeature >>>> kWebGPUCompatibilityMode controls the JS API in the renderer process >>>> >>>> >>>> *Debuggability* >>>> *No information provided* >>>> >>>> *Will this feature be supported on all six Blink platforms (Windows, >>>> Mac, Linux, ChromeOS, Android, and Android WebView)?* >>>> No >>>> All platforms will eventually have support. Will immediately be >>>> available on Android, Android WebView, ChromeOS, Mac, and Windows, where >>>> hardware support is available. Linux is planned to have WebGPU support in >>>> the future, so this feature will become available when WebGPU does. >>>> >>>> *Is this feature fully tested by web-platform-tests >>>> <https://chromium.googlesource.com/chromium/src/+/main/docs/testing/web_platform_tests.md>?* >>>> Yes >>>> All Compatibility Mode restrictions are exercised by the >>>> "compatibility" option to the WebGPU CTS. E.g., >>>> https://gpuweb.github.io/cts/standalone/?compatibility=1&q=webgpu:* >>>> This subset is tested extensively on the Dawn CI ( >>>> https://ci.chromium.org/p/chromium/g/chromium.dawn/console) under the >>>> "webgpu_cts_compat_tests" suite. WebGPU/WGSL have a conformance test suite >>>> ( >>>> https://github.com/gpuweb/cts) that is regularly pulled into Chromium >>>> and part of the testing of Dawn/Tint in Chromium. While the CTS can be >>>> embedded in WPT, the WebGPU team opted to keep it separate in Chromium >>>> testing to use a customized harness for robustness and performance. >>>> >>>> *Flag name on about://flags* >>>> *No information provided* >>>> >>>> *Finch feature name* >>>> WebGPUCompatibilityMode >>>> >>>> *Rollout plan* >>>> Will ship enabled for all users >>>> >>>> *Requires code in //chrome?* >>>> False >>>> >>>> *Tracking bug* >>>> https://crbug.com/442618060 >>>> >>>> *Availability expectation* >>>> Mozilla is interested in this feature (and has approved all of the spec >>>> changes) but has not committed to implementing it yet. Apple has approved >>>> all of the spec changes, but it is not anticipated that this feature will >>>> ship in Safari since all Apple devices on the market can support the full >>>> Core WebGPU spec. However, since it is designed as a subset, Compatibility >>>> mode applications will work unchanged in browsers that only support Core >>>> (e.g., Safari). >>>> >>>> *Adoption expectation* >>>> Feature is used by specific partner(s) to provide functionality within >>>> 12 months of launch in Chrome. >>>> >>>> *Adoption plan* >>>> Adoption of Core WebGPU proceeds apace (https://chromestatus.com/ >>>> metrics/feature/timeline/popularity/4029), and it is expected that >>>> developers will adopt Compatibility Mode because it allows them to extend >>>> the reach of their WebGPU content to a larger audience. >>>> >>>> *Non-OSS dependencies* >>>> >>>> Does the feature depend on any code or APIs outside the Chromium open >>>> source repository and its open-source dependencies to function? >>>> On Android, this feature depends on the OpenGLES 3.1 graphics API in >>>> order to provide WebGPU capability to older devices. The JavaScript API >>>> will be available on all platforms, including desktop, but will not require >>>> any new graphics APIs; it will simply allow developers to test the >>>> Compatibility Mode subset on all Chrome platforms. >>>> >>>> *Estimated milestones* >>>> Shipping on desktop146 Origin trial desktop first139 Origin trial >>>> desktop last145 Shipping on Android146 Origin trial Android first139 Origin >>>> trial Android last145 Shipping on WebView146 Origin trial WebView first >>>> 139 Origin trial WebView last145 >>>> >>>> *Anticipated spec changes* >>>> >>>> Open questions about a feature may be a source of future web compat or >>>> interop issues. Please list open issues (e.g. links to known github issues >>>> in the project for the feature specification) whose resolution may >>>> introduce web compat/interop risk (e.g., changing to naming or structure of >>>> the API in a non-backward-compatible way). >>>> All Compatibility Mode changes have landed in the WebGPU core spec: >>>> https://www.w3.org/TR/webgpu/; all known issues have been addressed. >>>> >>>> *Link to entry on the Chrome Platform Status* >>>> https://chromestatus.com/feature/6436406437871616?gate=6221450639572992 >>>> >>>> *Links to previous Intent discussions* >>>> Intent to Experiment: https://groups.google.com/a/ >>>> chromium.org/d/msgid/blink-dev/683618d7.170a0220.2aa17e. >>>> 17c5.GAE%40google.com >>>> >>>> >>>> This intent message was generated by Chrome Platform Status >>>> <https://chromestatus.com>. >>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "blink-dev" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to [email protected]. >>>> To view this discussion visit >>>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/2c05e366-fc6b-453d-a4a6-86f3c38076f9n%40chromium.org >>>> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/2c05e366-fc6b-453d-a4a6-86f3c38076f9n%40chromium.org?utm_medium=email&utm_source=footer> >>>> . >>>> >>> -- > You received this message because you are subscribed to the Google Groups > "blink-dev" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion visit > https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAPeKFTh6JnVoWujtuFteRnMPg3Qt8Fi%2B3J0bc5ea78hcVMDa9Q%40mail.gmail.com > <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAPeKFTh6JnVoWujtuFteRnMPg3Qt8Fi%2B3J0bc5ea78hcVMDa9Q%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "blink-dev" group. 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