Next.js 15 Released: Async Request APIs and React 19 Support

What happened

Next.js 15 was released as stable on October 21, 2024, according to the official Next.js blog. Built on the earlier release candidates, it focused on stability while introducing several breaking changes that set the stage for a simpler rendering and caching model.

Async request APIs

The most significant breaking change is that APIs relying on request-specific data, including cookies, headers, draftMode, and params and searchParams in pages and layouts, became asynchronous. The reasoning is that not all components depend on request data, so making these APIs async lets the server prepare more work before a request arrives. Next.js shipped a codemod and a temporary synchronous-access fallback to ease migration.

New caching defaults

Next.js 15 changed the App Router's opinionated caching defaults. GET route handlers and the client router cache moved from cached by default to uncached by default, so navigations reflect the latest data unless a developer opts back into caching. This addressed feedback that the previous defaults were surprising and interacted awkwardly with third-party libraries and partial prerendering.

React 19 and stable Turbopack

The release aligned with React 19, using the React 19 RC in the App Router while keeping backwards compatibility with React 18 in the Pages Router. It also marked next dev --turbo, the Rust-based Turbopack for development, as stable, with Vercel reporting large improvements in local server startup and Fast Refresh on its own applications. Other additions included support for a TypeScript next.config.ts file and a new Form component.

Why it mattered

Next.js 15 was a foundational release: async request APIs and the new caching defaults are breaking, but they simplify the mental model and unlock future optimisations such as partial prerendering. Combined with React 19 alignment and stable Turbopack dev, it pushed the framework toward faster builds and a clearer separation between static and dynamic rendering, with codemods provided to smooth the upgrade.

Related on Skillo

See also: Next.js 14 and stable Server Actions, React 19's Actions and stable Server Components.

Sources

• Next.js 15 (official Next.js blog)

Published date reflects the original event date (2024-10-21). This article is original Skillo editorial written from the sources above; facts were verified in September 2026.