What's New in WebGPU (Chrome 136)
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François Beaufort

Published: April 23, 2025

GPUAdapterInfo isFallbackAdapter attribute

The GPUAdapterInfo isFallbackAdapter boolean attribute indicates whether a GPUAdapter has significant performance limitations in exchange for wider compatibility, more predictable behavior, or improved privacy. This addition was necessary because libraries that take user-provided GPUDevice objects couldn't access this information through the adapterInfo attribute on GPUDevice. See the following example and issue 403172841.

const adapter = await navigator.gpu.requestAdapter();

if (adapter?.info.isFallbackAdapter) {
  // The returned adapter is a software-backed fallback adapter, which
  // may have significantly lower performance and fewer features.
}

Since Chrome has not yet shipped support for fallback adapters, isFallbackAdapter is at the moment always false on users' devices. We're investigating whether the GPUAdapter isFallbackAdapter attribute can be deprecated and removed. See intent to ship.

Shader compilation time improvements on D3D12

The Chrome team keeps improving Tint, the WebGPU shader language compiler, by adding an intermediate representation (IR) for devices that support WebGPU with the D3D12 backend. This IR, positioned between Tint's abstract syntax tree (AST) and the HLSL backend writer, will make the compiler more efficient and maintainable, ultimately benefiting both developers and users. Initial tests show that the new version of Tint is up to 10 times faster when translating Unity's WGSL shaders to HLSL.

A flowchart shows the process of converting WGSL shader code into low-level GPU instructions. — Render pipeline creation in Windows.

These improvements—already accessible on Android, ChromeOS, and macOS—are being progressively expanded to Windows devices that support WebGPU with the D3D12 backend. See issue 42251045.

Save and copy canvas images

Chrome users can now right-click on a WebGPU canvas and access context menu options Save Image As… or Copy Image. See issue 40902474.

The — User selected "Save Image As…" context menu.

Lift compatibility mode restrictions

The experimental "core-features-and-limits" feature when available on a GPUDevice, lifts all compatibility mode restrictions (features and limits) when the chrome://flags/#enable-unsafe-webgpu flag is enabled. See issue 395855517.

Requesting a GPUAdapter with the featureLevel: "compatibility" option hints the browser to select the experimental WebGPU compatibility mode. If successful, the resulting adapter is "compatibility-defaulting". Otherwise, it is "core-defaulting", which is the same as using the featureLevel: "core" option. Moreover, calling requestDevice() without requiredFeatures and requiredLimits request a GPUDevice with the GPUAdapter's default capabilities.

Core-defaulting adapters always support the "core-features-and-limits" feature and it is automatically enabled on GPUDevices created from them. For compatibility-defaulting adapters, the "core-features-and-limits" feature may be supported and can be requested on GPUDevices created from them. Both types of adapters may also support features like "float32-blendable", which is optional in both core and compatibility modes.

The following example is for an application that requires "float32-blendable" and supports using core features if available, but uses only compatibility features if core features are not available.

const adapter = await navigator.gpu.requestAdapter({ featureLevel: "compatibility" });

if (!adapter || !adapter.features.has("float32-blendable")) {
  throw new Error("32-bit float textures blending support is not available");
}

const requiredFeatures = [];
if (adapter.features.has("core-features-and-limits")) {
  requiredFeatures.push("core-features-and-limits");
}

const device = await adapter.requestDevice({ requiredFeatures });

if (!device.features.has("core-features-and-limits")) {
  // Compatibility mode restrictions validation rules will apply.
}

The experimental GPUAdapter featureLeveland isCompatibilityMode attributes have been removed in favor of the "core-features-and-limits" feature. See issue 395855516.

Dawn updates

The callback status enum InstanceDropped has been renamed to CallbackCancelled to clarify that the callback was cancelled, but background processing associated with the event, such as pipeline compilation, might still be running. The new name is more generally-applicable, in case another cancellation mechanism is added later. See issue 520.