# .aac MIME Type: audio/aac

> Raw AAC audio in an ADTS stream. Most AAC files you meet are in .m4a containers instead.

- MIME type: `audio/aac`
- Extensions: .aac
- Content-Type header: `audio/aac`
- Compress in transit: no (already compressed)

## Good to know

- For podcasts and downloads, `.m4a` (`audio/mp4`) is better supported than raw `.aac`.

## Server configuration

### nginx (inside the types block in mime.types)

```
audio/aac aac;
```

### Apache (.htaccess or server config)

```
AddType audio/aac .aac
```

### Express

```
res.set("Content-Type", "audio/aac");
```

### Python

```
import mimetypes

mimetypes.add_type("audio/aac", ".aac")
```

### HTML file input

```
<input type="file" accept=".aac,audio/aac">
```

## FAQ

### What is the MIME type for .aac files?

`audio/aac`.

### What Content-Type header should a .aac file be served with?

`Content-Type: audio/aac`. It's already compressed, so servers shouldn't gzip it.

## Related types

- [.m4a — audio/mp4](https://www.devkult.com/mime/m4a.md)
- [.mp3 — audio/mpeg](https://www.devkult.com/mime/mp3.md)

Open the interactive page: https://www.devkult.com/mime/aac