MIME Type

GET/v0/mime-type

Validates a MIME type (media type) string against the IANA media type registry. Input is case-insensitive and optional parameters (e.g. ;charset=utf-8) are stripped before lookup. When valid, returns the type, subtype, associated file extensions, compressibility, and charset.

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Query Parameters

Parameter	Type	Required	Description
value	string	Yes	MIME type string, case-insensitive (e.g. `application/json`, `image/png`, `text/html;charset=utf-8`)

Example Requests

curl -H "Authorization: Bearer YOUR_API_KEY" \
  "https://api.isvalid.dev/v0/mime-type?value=application/json"

Response Fields

Field	Type	Description
valid	boolean	Whether the value is a registered MIME type
mime	string	Canonical MIME type string
type	string	Top-level type (e.g. application, image, text)
subtype	string	Subtype (e.g. json, png, html)
extensions	string[]	Associated file extensions (without dot)
compressible	boolean \| null	Whether the content is compressible
charset	string \| null	Default charset (e.g. UTF-8)
source	string \| null	Registration source (iana, apache, nginx)

Example Response

{
  "valid": true,
  "mime": "application/json",
  "type": "application",
  "subtype": "json",
  "extensions": ["json", "map"],
  "compressible": true,
  "charset": "UTF-8",
  "source": "iana"
}

Example Response — invalid

{
  "valid": false
}

GET/v0/mime-type/ext

Looks up MIME types by file extension. The leading dot is optional (both .json and json are accepted). Some extensions map to multiple MIME types (e.g. js maps to both application/javascript and text/javascript).

Query Parameters

Parameter	Type	Required	Description
value	string	Yes	File extension, with or without leading dot (e.g. `json`, `.png`, `html`)

Example Requests

curl -H "Authorization: Bearer YOUR_API_KEY" \
  "https://api.isvalid.dev/v0/mime-type/ext?value=json"

Response Fields

Field	Type	Description
valid	boolean	Whether any MIME type is associated with this extension
extension	string	Normalized extension (without dot)
mimeTypes	object[]	Array of matching MIME types with full details

Example Response

{
  "valid": true,
  "extension": "json",
  "mimeTypes": [
    {
      "mime": "application/json",
      "type": "application",
      "subtype": "json",
      "extensions": ["json", "map"],
      "compressible": true,
      "charset": "UTF-8",
      "source": "iana"
    }
  ]
}

Example Response — not found

{
  "valid": false,
  "extension": "xyz123"
}

GET/v0/mime-type/list

Returns the complete list of all 2,500+ registered MIME types with their type, subtype, and associated file extensions. Optionally filter by top-level type.

Query Parameters

Parameter	Type	Required	Description
type	string	No	Filter by top-level type, case-insensitive (e.g. `image`, `application`, `text`)

Example Request

curl -H "Authorization: Bearer YOUR_API_KEY" \
  "https://api.isvalid.dev/v0/mime-type/list?type=image"

Object Fields

Field	Type	Description
mime	string	MIME type string
type	string	Top-level type
subtype	string	Subtype
extensions	string[]	Associated file extensions

Example Response

[
  { "mime": "application/json", "type": "application", "subtype": "json", "extensions": ["json", "map"] },
  { "mime": "image/png", "type": "image", "subtype": "png", "extensions": ["png"] },
  { "mime": "text/html", "type": "text", "subtype": "html", "extensions": ["html", "htm", "shtml"] },
  ...
]