Next.js 12 introduces new middleware that gives developers the ability to rapidly personalize content and delivery, in addition to ES modules and URL imports, instant HMR and builds, and significant workflow and collaboration innovations.
“Next.js 12 is truly the first SDK for the Web, making developing, building, collaborating and shipping far faster and more reliable than anything that precedes it,” said Guillermo Rauch, CEO of Vercel and creator of Next.js.
With Next.js Middleware, developers have full flexibility to run code before a request is completed. Based on users’ incoming requests, developers can modify the response by rewriting, redirecting, adding headers, or even streaming HTML. Middleware can be used for anything that shares logic for a set of pages: authentication, bot protection, redirects, handling unsupported browsers, feature flags, a/b tests, server-side analytics, logging, and more. Deployed with Vercel’s Edge Functions, Next.js Middleware removes the remaining tradeoffs with serverless.
Additional new features in Next.js 12 include:
- ES Modules and URL imports: With ES Modules support, Next.js can ship smaller bundles to users. The developer experience gets even better with the introduction of experimental URL Imports, enabling new kinds of seamless integrations with no code and design tools
- Instant HMR and builds: The new Next.js 12 Rust-based compiler enables three times faster Fast Refresh and five times faster production builds, with zero code changes
- Next.js Live (beta) enhancements: Next.js Live runs natively inside the web browser, boots up instantly and allows anyone with a link to collaborate