---
title: "MimeTypeDefinition"
source: "https://github.com/remix-run/remix/blob/8905f3943706e1f53696ab83e70a84873cabfc90/packages/mime/src/lib/define-mime-type.ts#L4"
---

# MimeTypeDefinition

## Summary

Definition used to register a custom MIME type.

## Signature

```ts
interface MimeTypeDefinition {
  charset?: string
  compressible?: boolean
  extensions: string | string[]
  mimeType: string
}

```

## Properties

### `charset`

Charset to include in Content-Type header.
- `'utf-8'` or other string → '; charset={value}'
- `undefined` → falls back to default heuristics (`'utf-8'` for `text/*`, `application/json`, `+json`)

### `compressible`

Whether this MIME type is compressible.
If omitted, falls back to default heuristics (text/*, +json, +text, +xml).

### `extensions`

The file extension(s) to register (e.g., ['x-myformat'])

### `mimeType`

The MIME type for these extensions (e.g., 'application/x-myformat')