Middleware

Middleware

Lightweight request interception running at the edge (V8 runtime). Use for redirects, rewrites, auth guards, A/B testing, and header injection.

⚠️ Framework projects (Next.js, Nuxt, etc.): Do NOT use this platform middleware format. Use the framework's built-in middleware instead (e.g. Next.js middleware.ts with NextRequest/NextResponse). The patterns below are for non-framework or pure static projects only.

Basic middleware

File: middleware.js (project root)

export function middleware(context) {
  const { request, next, redirect, rewrite } = context;

  // Pass through — no modification
  return next();
}

Context API

Route matching

By default middleware runs on ALL routes. Use config.matcher to limit scope:

// Only run on /api/* routes
export const config = {
  matcher: ['/api/:path*'],
};