React 19 shipped a laundry list of features. Twitter threads treated every hook like mandatory. In production on client sites and this portfolio, I adopted a subset — the ones that remove real bugs or UX jank — and ignored the rest until the ecosystem caught up. This is my honest react 19 features guide: what changed, code you can paste, and what I am still waiting on.
What actually changed at a high level
React 19 stabilised the Actions model (forms and mutations with pending state), added useOptimistic for instant UI feedback, introduced the use() hook for reading promises and context, improved hydration error messages, and made ref-as-prop cleaner. The compiler (React Forget) is separate — exciting, not required to upgrade.
Upgrade path: Next.js 15 projects already pin compatible React versions. Read RSC vs client components before mixing Actions with Server Components — boundaries still matter.
React 19 hooks and APIs — quick reference table
