# Response The `Response` interface represents an HTTP response in the [Fetch API](/en/documentation/devtools/runtime/api-reference/fetch/) of Azion Runtime. A function answers a request by returning a `Response` from its [handler](/en/documentation/devtools/runtime/api-reference/handlers/), and `fetch()` resolves to a `Response`. For more information, refer to [Response](https://developer.mozilla.org/en-US/docs/Web/API/Response) on MDN Web Docs. > **Note** > > Under `azion dev`, a response that `fetch()` returns reports `type` as `default`, not `basic`, and `redirected` stays `false` after `fetch()` follows a redirect. A response you construct reports the same values in both environments. --- ## Constructor ```javascript new Response(body, init) ``` | Parameter | Type | Required | Default | Description | | --------- | -------------------------------------- | -------- | ------- | ------------------------------------------------------------ | | `body` | One of the body types below, or `null` | No | `null` | Content of the response body. | | `init` | Object | No | `{}` | Options that set the status and the headers of the response. | The `body` parameter accepts these types. Three of them set a `content-type` header on the response: | Body type | `content-type` set by the constructor | | ------------------------------------------------------------------------------------- | ------------------------------------------------- | | [`Blob`](https://developer.mozilla.org/en-US/docs/Web/API/Blob) | None | | `BufferSource`, such as a `Uint8Array` | None | | [`FormData`](https://developer.mozilla.org/en-US/docs/Web/API/FormData) | `multipart/form-data; boundary=` | | [`ReadableStream`](https://developer.mozilla.org/en-US/docs/Web/API/ReadableStream) | None | | [`URLSearchParams`](https://developer.mozilla.org/en-US/docs/Web/API/URLSearchParams) | `application/x-www-form-urlencoded;charset=UTF-8` | | [`USVString`](https://developer.mozilla.org/en-US/docs/Web/API/USVString) (a string) | `text/plain;charset=UTF-8` | | `null` | None; the body reads as an empty string | The `init` object takes these options: | Option | Type | Description | | ------------ | ---------------------------------------------------------------------------------------------- | ----------------------------------------------------------------- | | `status` | Number | Status code of the response, such as `201`. | | `statusText` | String | Status message that goes with the status code, such as `Created`. | | `headers` | [`Headers`](https://developer.mozilla.org/en-US/docs/Web/API/Headers) object or a plain object | Headers of the response. | The constructor ignores a `url` option: the `url` property of a constructed response is an empty string. --- ## Properties `Response` implements the body of the Fetch API, so it carries `body` and `bodyUsed` beside its own properties: | Property | Type | Description | | ------------ | ---------------- | --------------------------------------------------------------------------------------------------------------------------------------------------- | | `body` | `ReadableStream` | Body content, read as a stream. For more information, refer to [ReadableStream](/en/documentation/devtools/runtime/api-reference/readable-stream/). | | `bodyUsed` | Boolean | `true` after the body is read. | | `headers` | `Headers` | Headers of the response. | | `ok` | Boolean | `true` when `status` is in the range 200–299. | | `redirected` | Boolean | `true` when `fetch()` followed at least one redirect to reach the response. | | `status` | Number | Status code of the response, such as `200`. | | `statusText` | String | Status message that goes with the status code, such as `OK` for `200`. | | `type` | String | Type of the response: `basic` for a response from `fetch()`, `default` for a response you construct, and `error` for `Response.error()`. | | `url` | String | Final URL of a response from `fetch()`, after redirects. An empty string on a response you construct. | --- ## Methods | Method | Description | | -------------------------------- | ----------------------------------------------------------------------------------------------------------- | | `response.clone()` | Returns a copy of the response. The copy and the original each read the full body. | | `response.json()` | Reads the body and parses it as JSON. Returns a promise. | | `response.text()` | Reads the body as a string. Returns a promise. | | `Response.error()` | Static. Returns a response with `type` `error` and `status` `0`. | | `Response.json(data)` | Static. Returns a response whose body is `data` serialized as JSON, with `content-type` `application/json`. | | `Response.redirect(url, status)` | Static. Returns a redirect response with the `status` you pass and a `location` header set to `url`. | `redirect()` exists only as a static method: call `Response.redirect()`, because a `Response` instance has no `redirect` method. --- ## Example This handler constructs a response with a status, a status message, a header, and a `url` option, then returns the properties of the response with `Response.json()`: ```javascript export default { async fetch(request, env, ctx) { const response = new Response('x', { status: 201, statusText: 'Created', headers: { 'x-h': '1' }, url: 'https://ignored.example/', }); return Response.json({ status: response.status, statusText: response.statusText, ok: response.ok, redirected: response.redirected, type: response.type, url: response.url, useFinalURL: response.useFinalURL, header: response.headers.get('x-h'), bodyType: response.body?.constructor?.name, bodyUsed: response.bodyUsed, }); }, }; ``` The function returns these values from the response. `"[undefined]"` marks a property that is `undefined`, and `url` is empty because the constructor ignores the `url` option: ```json { "status": 201, "statusText": "Created", "ok": true, "redirected": false, "type": "default", "url": "", "useFinalURL": "[undefined]", "header": "1", "bodyType": "ReadableStream", "bodyUsed": false } ``` --- ## Related resources - [fetch](/en/documentation/devtools/runtime/api-reference/fetch.md): How a function sends a request and receives a `Response`. - [Request](/en/documentation/devtools/runtime/api-reference/request.md): The incoming request, and how to build one to pass to `fetch()`. - [ReadableStream](/en/documentation/devtools/runtime/api-reference/readable-stream.md): How to read or produce a response body as a stream. - [Web APIs](/en/documentation/devtools/runtime/api-reference/javascript.md): The other Web APIs that Azion Runtime supports.