---
title: res.type
description: Sets the Content-Type HTTP header to the MIME type as determined by the specified type. If type contains the slash character, then it sets the Content-Type to the exact value.
---

<h3 id='res.type'>res.type(type)</h3>

Sets the `Content-Type` HTTP header to the MIME type as determined by the specified `type`. If `type` contains the "/" character, then it sets the `Content-Type` to the exact value of `type`, otherwise it is assumed to be a file extension and the MIME type is looked up in a mapping using the `express.static.mime.lookup()` method.

```js
res.type('.html');
// => 'text/html'
res.type('html');
// => 'text/html'
res.type('json');
// => 'application/json'
res.type('application/json');
// => 'application/json'
res.type('png');
// => 'image/png'
```

Aliased as `res.contentType(type)`.
