# Api Routes

Simple API routes inside Next.js app like for form input

Just create a **function** inside the `pages/api` directory that has the following format:

/pages/api/hello.js

```ts
import type { NextApiRequest, NextApiResponse } from 'next'
 
type ResponseData = {
  message: string
}
 
export default function handler(
  req: NextApiRequest,
  res: NextApiResponse<ResponseData>
) {
  res.status(200).json({ message: 'Hello from Next.js!' })
}
```

<http://localhost:3000/api/hello>

They can be deployed as Serverless Functions (also known as Lambdas).

* `req` is an instance of [http.IncomingMessage](https://nodejs.org/api/http.html#http_class_http_incomingmessage), plus some pre-built middlewares you can see [here](https://nextjs.org/docs/api-routes/api-middlewares).
* `res` is an instance of [http.ServerResponse](https://nodejs.org/api/http.html#http_class_http_serverresponse), plus some helper functions you can see [here](https://nextjs.org/docs/api-routes/response-helpers).

**Do Not Fetch an API Route from `getStaticProps` or `getStaticPaths`**, instead just run the code in them since it runs serverside anyway

[Dynamic Api Routes](https://nextjs.org/docs/api-routes/dynamic-api-routes)


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://openai.gitbook.io/code-cheatsheets/react/next/preapprouter/api.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.