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Usually, no: for new code, React recommends letting React Compiler handle ordinary callback memoization instead of wrapping every handler in useCallback. Keep the hook when you need precise control, and do not remove existing calls across a codebase without testing. The compiler is a build-time optimizer—not a guarantee that every function is cached.
How React Compiler changes callback memoization
React Compiler analyzes components and Hooks at build time and can add memoization automatically. React’s recommendation is to rely on that analysis for new code and use useMemo or useCallback when you need precise control. This reduces manual bookkeeping; it is not a promise that every callback will be optimized or a measured speed improvement for every app. See the React Compiler introduction and the React team’s October 7, 2025 React Compiler 1.0 announcement.
Why wrapping a handler may not be enough
Suppose a component memoizes handleClick with useCallback, then passes () => handleClick(item) to each item in a list. That inline arrow function is still newly created during each render, so the child receives a new prop identity. React’s compiler introduction uses this pattern to show how the compiler can optimize code that manual memoization may leave unstable. It illustrates less bookkeeping, not a benchmark.
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When to keep useCallback
useCallback remains useful when you need deliberate control over a function’s identity. One example is a callback used as an Effect dependency, where a stable identity can prevent an Effect from running again when its meaningful inputs have not changed. React describes useCallback as a performance optimization; its cached value can be discarded in specific circumstances, so correctness must not depend on the cache. Consult the useCallback API reference.
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- Keep it when you have a specific, understood need for a stable function reference.
- Do not add it reflexively to every event handler just because the function is passed to a child.
- Do not make program behavior depend on a callback retaining the same identity forever.
Should you remove useCallback from existing code?
Not in a sweeping cleanup. React advises leaving existing manual memoization in place or testing carefully before removing it, because existing annotations can affect the compiler’s output. A change that seems like a harmless deletion may alter referential equality or Effect behavior.
Before removing a call, check what depends on the stable identity, then run the relevant tests—including end-to-end tests for important user flows. React’s adoption guidance recommends gradual rollout so teams can check behavior and performance in a small part of an app before expanding.
What the compiler does—and does not—memoize
The compiler primarily targets component update performance: it can skip cascading re-renders and memoize selected calculations in components and Hooks. It does not automatically memoize every plain JavaScript function, and memoized calculations are not shared as a common cache across separate components or Hooks. For expensive work shared across components, profile the application before choosing another memoization strategy. React explains these boundaries in its compiler introduction.
Is React Compiler ready for an app?
React announced React Compiler 1.0 as stable and production-ready on October 7, 2025, and said it had been used at Meta. Stable does not mean every application should enable it everywhere immediately: React’s guidance still ties successful adoption to codebase health, the Rules of React, and incremental verification.
The official installation guide lists React 17, 18, and 19 as supported, with React 19 the best fit, and documents the Babel plugin plus integrations for Babel, Vite, Metro, and Rsbuild. React’s introduction describes Next.js 15.3.1 and later as supporting the compiler invoked through SWC. These integration details can change, so check the current guide for your framework and versions.
A cautious rollout
- Confirm your React and build-tool versions against the current installation guide.
- Enable compilation for a small, representative part of the application first, and verify behavior and performance before expanding.
- Use the documented runtime gating or annotation-mode options if you need a controlled rollout; annotation mode compiles functions marked with
"use memo". - Check React DevTools for the “Memo ✨” badge to confirm a component is being compiled.
- If a specific component causes a problem, React documents
"use no memo"as a temporary way to opt it out while investigating.
Follow the adoption guide and troubleshooting guidance. Pay particular attention to code that relies on referential equality or stable references in Effect dependencies: changed memoization can cause Effects to run too often, loop, or miss updates. Keep memoization out of correctness requirements and test upgrades.
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