Detect file type from magic bytes API

Sniff a file type from its leading bytes (supplied as hex or base64) by matching against a table of well-known magic-number signatures (PNG, JPEG, GIF, PDF, ZIP/Office, gzip, WebP, MP3/ID3, MP4 ftyp, ELF, Windows PE, and more), returning the detected MIME type, canonical extension, category, and the matched signature with its byte offset. Content-based, not extension-based, so it catches mislabeled/spoofed files. Answers 'what file type are these bytes','is this really a PNG','detect MIME from a base64 prefix'.

Price$0.01per request

MethodPOST

Route/v1/util/util-mime-magic

StatusLive

MIME typeapplication/json

Rate limit120/minute

CacheNo cache

utilmimemagic-numberfile-typesignaturesniffbinarydetect

API URLhttps://x402.hexl.dev/v1/util/util-mime-magic

Integration docs

Example request

{
  "hex": "89504E470D0A1A0A"
}

Example response

{
  "detected": true,
  "mime": "image/png",
  "extension": "png",
  "category": "image",
  "signature": "PNG",
  "matchedHex": "89504E470D0A1A0A",
  "offset": 0,
  "bytesInspected": 8,
  "prefixHex": "89 50 4E 47 0D 0A 1A 0A"
}

Input schema

{
  "type": "object",
  "required": [],
  "properties": {
    "bytes": {
      "type": "string",
      "examples": [
        "89504E470D0A1A0A"
      ]
    },
    "hex": {
      "type": "string",
      "examples": [
        "89504E470D0A1A0A"
      ]
    },
    "base64": {
      "type": "string",
      "examples": [
        "JVBERi0xLjQ="
      ]
    },
    "encoding": {
      "type": "string",
      "enum": [
        "hex",
        "base64"
      ],
      "examples": [
        "hex"
      ]
    }
  },
  "examples": [
    {
      "hex": "89504E470D0A1A0A"
    },
    {
      "base64": "JVBERi0xLjQ="
    }
  ]
}

Output schema

{
  "type": "object",
  "additionalProperties": true
}