Engineering28 June 2026·8 min read
A Practical React Performance Checklist
The handful of techniques that actually moved the needle across three years of production React work.
Most React performance advice is premature. These are the checks I run only after a real measurement shows a real problem.
Measure before you optimise
The React Profiler and a Lighthouse trace will tell you more in five minutes than a day of guessing. Slow renders and slow networks look identical to users but need opposite fixes.
Stabilise what crosses boundaries
Memoisation only pays off where a new reference cascades. Stable callbacks, keyed lists and colocated state usually remove the need for memo entirely.
Ship less JavaScript
Route-level code splitting, server rendering the first paint and lazy-loading heavy widgets beat every micro-optimisation combined.
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