TOPIC OVERVIEW

nextjs/Route Handlers

Building an API endpoint directly inside the App Router, using a route.ts file.

10 QuestionsIntermediateHigh Priority ~11 min read

A route.ts (or .js) file inside the App Router defines a Route Handler — the App Router's replacement for the Pages Router's API routes. It exports functions named after HTTP methods (GET, POST, PUT, DELETE) that receive a standard Web Request and return a standard Web Response, rather than the Next-specific req/res objects the Pages Router used.

A route segment can be a page or a Route Handler, but not both — page.tsx and route.ts can't coexist in the same folder. GET Route Handlers are cached by default unless they read dynamic request data or explicitly opt out, and — like any other route — a Route Handler can run on either the Node or Edge runtime depending on what it actually needs to do.

What you'll walk away knowing

How a Route Handler is defined (route.ts, exported HTTP-method functions) and how it differs from Pages Router API routes

Why route.ts and page.tsx can't both exist in the same route segment

When a GET Route Handler is cached by default, and how to opt it out of caching

How to choose between the Node and Edge runtime for a given Route Handler

1What are Route handlers?ExpertHigh 2List methods supported by route handlers in next js?ExpertHigh 3How to redirect in route handlers?ExpertHigh 4What is the difference between API Routes (Pages Router) and Route Handlers (App Router)? What new capabilities do Route Handlers have?ExpertHigh 5How do you implement a streaming response from a Route Handler in Next.js?ExpertHigh 6How do Route Handlers interact with Next.js caching? How do you make a Route Handler static vs dynamic?ExpertHigh 7Can Route Handlers replace a separate backend entirely? What are the architectural trade-offs?ExpertHigh 8How do you implement rate limiting on a Next.js Route Handler without an external service?ExpertHigh 9How do you handle CORS in Next.js Route Handlers?ExpertHigh 10What is the difference between a Route Handler and a Server Action? When would you choose one over the other?ExpertHigh

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