Next.js 16 warns middleware is deprecated, and proxy.ts throws if you set runtime = 'edge'

Symptom

The "middleware" file convention is deprecated. Please use "proxy" instead.Build error after renaming to proxy.ts with export const runtime = 'edge' still in the fileEdge-only code paths in middleware now run on Node.js after the rename

Cause

Next.js 16 renamed middleware to proxy and fixed the proxy runtime to Node.js with no runtime option. Only the deprecated middleware file can still run on the Edge runtime.

Fix

Rename the file and the exported function to proxy, drop the runtime export, and rename config flags like skipMiddlewareUrlNormalize. Stay on middleware.ts if you truly need Edge.

ApplyCopy

npx @next/codemod@canary upgrade latest # or by hand mv middleware.ts proxy.ts # export function proxy(request: NextRequest) { ... }

Affected

Next.js 16.0 and later

Sources

• https://nextjs.org/docs/app/guides/upgrading/version-16
• https://nextjs.org/docs/app/api-reference/file-conventions/proxy

Last verified 2026-10-15 · Confirmed by 0 builders