Below is a list of all new features, APIs, and bug fixes.

Read the React 19.3 release post for more information.

New React Features

• <ViewTransition />: Adds <ViewTransition /> and addTransitionType APIs to power View Transition animations in React (@sebmarkbage, @jackpope, @gaearon: #31975, #31987, #31996, #31999, #32001, #32002, #32028, #32029, #32031, #32034, #32038, #32041, #32050, #32090, #32105, #32254, #32379, #32422, #32462, #32540, #32545, #32585, #32599, #32611, #32612, #32617, #32651, #32653, #32656, #32664, #32699, #32723, #32734, #32751, #32752, #32760, #32761, #32764, #32772, #32790, #32819, #32820, #32822, #32833, #32849, #33094, #33191, #33200, #33206, #33293, #33330, #33331, #33332, #33357, #33362, #33433, #33576, #34374, #34450, #34481, #34500, #34502, #34510, #34511, #34539, #35567, #35564, #35485, #35380, #35063, #35060, #34676, #36917, #35337, #35520)
• Fragment Refs: Add Refs to <Fragment /> to support composable platform behavior (@jackpope, @sebmarkbage, @eps1lon, @Dhakshin2007, @chirokas, @teamleaderleo, @fallintoplace: #32465, #32613, #32619, #32654, #32660, #32682, #32722, #32813, #32814, #33056, #33058, #33093, #34069, #34103, #34544, #34545, #37062, #37061, #37060, #36047, #36010, #35642, #35641, #35637, #35630, #34935, #37457, #37408, #37326, #37251, #37171, #37169, #37168, #37167, #37166, #37165, #37164, #37163, #37162, #37161, #37160, #37125, #37063)

New React DOM Features

• browser(): a new react-dom API that returns a usable which errors during server rendering and resolves in the browser. use(browser()) inside a <Suspense> boundary marks a subtree as browser-only without reporting a recoverable error (@gnoff: #37143, #37241)
  • Added an onBrowserBailout option to the react-dom/server APIs to observe when a subtree defers to the browser (@gnoff #37193)

Notable changes

• Enable Trusted Types API integration (@rickhanlonii #35816)
• Transitions now render independently instead of being entangled into a single render, so a slow transition no longer holds up unrelated ones (@acdlite #37290)
• Added a DEV-only warning when a component appears to have been unblocked by calling use() conditionally (@hoxyq, @eps1lon: #37104, #37203, #37491)

All Changes

React

• Fast Refresh Fixes
  • Fix Fast Refresh to find and remount edits to components wrapped behind lazy() (@sophiebits #36965)
  • Fix Fast Refresh so edits to a memo() comparison function take effect (@sophiebits #36964)
  • Fix Fast Refresh crash when an edit changes the kind of a component's type (@sophiebits #36963)
  • Unify hot reload type resolution for Fast Refresh (@sophiebits #36962)
  • Fix Fast Refresh to remount correctly when an edit changes the component kind (@sophiebits #36950)
  • Double invoke effects in StrictMode after Fast Refresh (@eps1lon #35962)
• Performance Track Fixes
  • Prevent crash when accessing $$typeof in Performance Tracks (@eps1lon #35679)
  • Handle non-string function names in Performance Tracks (@eps1lon #35659)
  • Use minus (-) instead of en dash for removed props in Performance Tracks (@eps1lon #35649)
  • Handle arrays with bigints in deep objects in Performance Tracks (@eps1lon #35648)
  • Don't enumerate typed array props in Performance Tracks in DEV (@UditDewan #36913)
  • Bail out of diffing wi...

React Server Components

• Performance improvements when decoding
  (#37087 by @eps1lon)

React Server Components

• Performance improvements when decoding
  (#37088 by @eps1lon)

React Server Components

• Performance improvements when decoding
  (#37089 by @eps1lon)

React Server Components

• Fixed missing FormData entries in Server Actions which regressed in 19.2.6
  (#36566 by @unstubbable)

React Server Components

• Fixed missing FormData entries in Server Actions which regressed in 19.1.7
  (#36567 by @unstubbable)

React Server Components

• Fixed missing FormData entries in Server Actions which regressed in 19.0.6
  (#36568 by @unstubbable)

React Server Components

• Type hardening and performance improvements
  (#36425 by @eps1lon and @unstubbable)

React Server Components

• Type hardening and performance improvements
  (#36425 by @eps1lon and @unstubbable)

React Server Components

• Type hardening and performance improvements
  (#36425 by @eps1lon and @unstubbable)