File Type Validator — verify file MIME and extension

Validate File Type API

Hosted on ApyHub

What it does

File Type Validator checks whether an uploaded file matches its filename extension and declared MIME type. Send a file or a file URL, and get back the original filename or URL, the extracted extension, the declared MIME type when provided, the detected MIME type from the file content, a boolean validity flag, and a human-readable message.

Use the direct upload endpoint when you receive multipart files from users or partners. The file input accepts a binary file up to 100 MB. The response tells you the file name, lowercased extension, declared MIME type, detected type, and whether the file is valid according to both checks. When you need to validate remote assets, the URL endpoint accepts a direct file URL with a recognisable extension and returns the validated URL, detected type, validity flag, and message.

This is useful for upload filters, document intake, attachment checks, and backend file safety rules. You can reject mismatched uploads, flag suspicious content types, or log validation results before passing files into conversion, storage, or processing workflows.

What you'll get back

Returns a JSON object with these required fields: file_name (string), extension (string), mime_type (string or null), detected_type (string or null), is_valid (boolean), and message (string).

{
  "file_name": "report.pdf",
  "extension": "pdf",
  "mime_type": "application/pdf",
  "detected_type": "application/pdf",
  "is_valid": true,
  "message": "File is valid"
}

About this endpoint

What it does

Validates an uploaded file by comparing the detected file type against the file extension and the MIME type declared by the client. It returns the original file name, extracted extension, declared MIME type, detected type, a boolean validity flag, and a human-readable message.

Request Body

Parameter	Type	Mandatory	Description
file	String	Yes	The file to validate. Maximum 100 MB. Binary upload.

Response

Returns a JSON object with file_name, extension, mime_type, detected_type, is_valid, and message fields. The response confirms whether the detected type matches both the extension and the declared MIME, and includes the relevant file details.

Parameter	Type	Mandatory	Description
file_name	String	Yes	Original filename as provided by the client.
extension	String	Yes	Lowercased file extension extracted from `file_name`.
mime_type	String	Yes	MIME type declared by the client (multipart `Content-Type` field). Nullable; `null` if not provided.
detected_type	String	Yes	MIME type detected from the file's binary content. Nullable; `null` if detection failed.
is_valid	Boolean	Yes	`true` when detected type matches both the extension and the declared MIME.
message	String	Yes	Human-readable validation result or mismatch explanation.

Notes

The uploaded file has a maximum size of 100 MB.

Body

Name

Type

Description

bodyREQUIRED

object

—

Max 100MB total per request (all files combined). Larger? Use this API's URL-based endpoint instead, if it has one.

curl -X POST "http://localhost:8080/apyhub/validate-file-type/url" \ -H "apy-token: $APY_TOKEN" \ -H "Content-Type: application/json" \ -d '{"file_url":"https://assets.apyhub.com/samples/sample.pdf"}'

About this endpoint

What it does

Validates a file accessible from a URL by inspecting the downloaded file and comparing its detected MIME type against the file URL. It returns the validated file_url, the detected file type, whether the file is valid, and a message.

Request Body

Parameter	Type	Mandatory	Description
file_url	String	Yes	Direct URL to the file to validate. Must be a URI and should include a recognisable file extension such as `.pdf`, `.jpg`, or `.docx`.

Response

Returns a JSON object with file_url, detected_type, is_valid, and message fields. file_url and message are strings, detected_type is a string and may be null, and is_valid is a boolean. The success response schema does not declare a specific status code.

Parameter	Type	Mandatory	Description
file_url	String	Yes	The URL that was validated.
detected_type	String	Yes	MIME type detected from the downloaded file's binary content. This field is nullable.
is_valid	Boolean	Yes	Indicates whether the file is valid.
message	String	Yes	Result message returned by the endpoint.

Validate File Type API

What it does

Quickstart

What you'll get back

About this endpoint

What it does

Request Body

Response

Notes

Body

Quickstart

What you'll get back

About this endpoint

What it does

Request Body

Response

Body

Errors any endpoint can return