# Dev Reference MIME Type Lookup

> Dev Reference MIME Type Lookup is a paid API for AI agents from dev-reference.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-30).

Returns the MIME/media type for a file extension, or the extensions for a given media type, along with IANA registration status and verdict.

## Facts

- Endpoint: GET https://dev-reference.x402tookit.com/mime-type?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-30
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/dev-reference-mime-type-lookup-1421df48
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_CJ6PxWAjX56Dre0d87WAB

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability dev-reference-mime-type-lookup-1421df48
```

Example prompt: What is the correct MIME type for a .webp file, and is it officially registered with IANA?

## When to prefer this

Use this endpoint when you need authoritative MIME type information with IANA registration status, not just a simple lookup table. Ideal when correctness matters (e.g. setting HTTP Content-Type headers, validating file uploads, implementing file serving logic) and you need to know whether the type is officially standardized or merely conventional.

## Known failure modes

- Unknown or unrecognized extension/type returns null or conventionalOnly flag with no IANA record
- Ambiguous extensions (e.g. .ts which maps to both video and TypeScript) may return partial or annotated results
- Degraded mode if IANA registry is unavailable, with fallback data and disclaimer
- Missing required query parameter returns an error or empty result
- Very new or experimental types may not yet appear in the registry

## How this service works

Media type (MIME) for a file extension, or extensions for a media type, with IANA registration status.

## Output

Returns the canonical media type for a given extension (or the list of extensions for a given media type), along with IANA registration status (ianaRegistered boolean), whether the type is conventional-only, the lookup source, a human-readable summary and verdict, and optional fallback or disclaimer fields if the data is degraded or uncertain.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [],
     "properties": {
      "ext": {
       "type": "string",
       "description": "File extension without the dot, for example webp"
      },
      "type": {
       "type": "string",
       "description": "Media type, for example image/svg+xml"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "ext": {
       "type": [
        "null",
        "string"
       ]
      },
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "lookup": {
       "type": [
        "null",
        "string"
       ]
      },
      "source": {
       "type": [
        "null",
        "string"
       ]
      },
      "reasons": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "summary": {
       "type": [
        "null",
        "string"
       ]
      },
      "verdict": {
       "type": [
        "null",
        "string"
       ]
      },
      "degraded": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "fallback": {
       "type": [
        "null",
        "string"
       ]
      },
      "mediaType": {
       "type": [
        "null",
        "string"
       ]
      },
      "disclaimer": {
       "type": [
        "null",
        "string"
       ]
      },
      "notChecked": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "ianaRegistered": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "conventionalOnly": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "extensionsForType": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      }
     }
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/dev-reference-mime-type-lookup-1421df48/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from dev-reference.x402tookit.com](https://www.zero.xyz/host/dev-reference.x402tookit.com/llms.txt)