# WebRef List MIME Types

> WebRef List MIME Types is a paid API for AI agents from webref.johnaio281.workers.dev, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-22).

Returns a searchable list of MIME types with content-type matching details for HTTP request/response handling

## Facts

- Endpoint: GET https://webref.johnaio281.workers.dev/api/web/list_mime_types?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-22
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/webref-list-mime-types-dd607b20
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_dKD-T5Y9-bFFvFK9j70r5

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 webref-list-mime-types-dd607b20
```

Example prompt: Can you look up all the MIME types in the 'image' category — I want to know the correct content-type strings to use when serving different image formats from my API?

## When to prefer this

Choose this endpoint when you need a programmatic, pay-per-call lookup of MIME types without signup or API keys — ideal for AI agents that need to resolve content-type strings on demand during HTTP request/response construction. Prefer this over static lookup tables when you need searchable, filterable, up-to-date MIME type data. Especially useful within automated workflows that already use the x402 or MPP payment protocol on Base.

## Known failure modes

- No results returned if query string matches nothing in the registry
- Limit parameter ignored or defaulted if invalid value passed
- Invalid HTTP method (POST, PUT, etc.) rejected — only GET, HEAD, DELETE allowed
- Network or worker errors returning 5xx if the underlying Cloudflare worker is unavailable
- Payment failure via x402/MPP if USDC balance is insufficient or payment protocol misconfigured

## How this service works

Web standards and time reference for AI agents: HTTP status codes with what the client should do, retry semantics, MIME types and content-type matching, request-method safety and idempotency, plus deadline arithmetic - time until a moment, weekday and business-day checks, duration conversion and Unix timestamps. Pay per call in USDC on Base via x402 or USDC on Tempo via MPP. No signup, no API key, no KYC.

## Output

A list of MIME type entries, each including the content-type string (e.g. 'application/json'), top-level media type, subtype, and any associated file extensions or descriptions. Results can be filtered by a search query or top-level type, and limited to a configurable number of entries (default 50).

## 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",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "limit": {
      "def": {
       "type": "default",
       "innerType": {
        "def": {
         "type": "number",
         "checks": []
        },
        "type": "number",
        "isFinite": true
       },
       "defaultValue": 50
      },
      "type": "default"
     },
     "query": {
      "def": {
       "type": "optional",
       "innerType": {
        "def": {
         "type": "string"
        },
        "type": "string"
       }
      },
      "type": "optional"
     },
     "topLevel": {
      "def": {
       "type": "optional",
       "innerType": {
        "def": {
         "type": "string"
        },
        "type": "string"
       }
      },
      "type": "optional"
     }
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/webref-list-mime-types-dd607b20/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from webref.johnaio281.workers.dev](https://www.zero.xyz/host/webref.johnaio281.workers.dev/llms.txt)