React Compiler performance gets major upgrades, and Fragment event handling is overhauled.
Status as of September 2, 2026
What is this repo?
React is the library that powers user interfaces for web and native apps. This codebase is the core React library itself, including the runtime, server-side rendering, developer tools, and the new React Compiler. It is the foundation that all React applications are built on, and it is actively being developed with a focus on performance, reliability, and new features like the compiler.
Snapshotbased on the last 30 days of activity
Key features8
- React Compiler Rust Crate PublishingNot live yetMerged into the main branch, but not released or deployed yet, so users don't have it.c5
Workflows to publish the React Compiler's Rust crates to crates.io have been added, along with version-bump scripts and contributor documentation. This is a behind-the-scenes step to make the compiler available as a standalone Rust library.
- Fragment Event HandlingNot live yetMerged into the main branch, but not released or deployed yet, so users don't have it.c6c7c12c28c30c31c32c33c34c35c36c37c38c39c41
A series of fixes and improvements have been made to how React handles events on Fragments. This includes scoping `once` listeners to the fragment, properly cleaning up listeners on signal abort, applying listeners to children inserted into portals, fixing `dispatchEvent` when the container is a Document, and ensuring text children get listeners. These changes make Fragment event behavior more consistent and reliable.
- React Compiler PerformanceNot live yetMerged into the main branch, but not released or deployed yet, so users don't have it.c2c3c20c21c22
Multiple optimizations have landed in the Rust-based React Compiler, reducing memory churn, allocations, and compile time. Changes include moving compiled function bodies instead of cloning them, using inline sets for aliasing values, avoiding deep AST clones, and reducing heap allocation for abstract values. These improvements make the compiler faster and more memory-efficient.
- Flight String DeduplicationNot live yetMerged into the main branch, but not released or deployed yet, so users don't have it.c24
The Flight protocol (used for server components) now deduplicates repeated strings, such as bundler chunk URLs in client reference metadata. This reduces the size of the serialized data, improving performance for routes with many client references.
- Browser Bailout APINot live yetMerged into the main branch, but not released or deployed yet, so users don't have it.c42c44
A new `ReactDOM.browser()` API and a corresponding `onBrowserBailout` option for Fizz (server-side renderer) have been added. This allows developers to mark parts of a component tree that should only render in the browser, and Fizz will gracefully bail out of server-rendering them. The API is designed to be lazy and cheap on the client.
- DevTools Profiler SearchNot live yetMerged into the main branch, but not released or deployed yet, so users don't have it.c47
The DevTools Profiler now has a search bar in the commit view (Flamegraph and Ranked charts), allowing developers to find a specific component within profiling data. Previously, search was only available in the live Components panel.
What you can tell developers
- Available now0Released and developer-facing, so it's safe to tell developers it's available now.
- Nothing released to users yet
- Coming6Developer-facing, but only merged or still in progress. Not released to developers yet.
- Fragment Event HandlingDevTools FixesBrowser Bailout APIDevTools Profiler SearchDevTools Timeline Profiler RemovalParallel Transitions Enabled
- Behind the scenes7Behind-the-scenes work your developers won't notice, like refactors, infra, tests, and deps.
- React Compiler Rust Crate PublishingReact Compiler PerformanceCI and Build ImprovementsTest Infrastructure UpdatesFlight String DeduplicationCompiler FixesServer Renderer Fixes