# PennyRail MIME Type Lookup

> PennyRail MIME Type Lookup is a paid API for AI agents from pennyrail.vercel.app, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-31).

Looks up the MIME type for a given file extension or filename via a paid micro-settlement API

## Facts

- Endpoint: POST https://pennyrail.vercel.app/api/p/nano/mime.lookup--proven-mime?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-31
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/pennyrail-mime-type-lookup-49b30d2b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ILJpsSTnY4xHXgHayo5Qn

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 pennyrail-mime-type-lookup-49b30d2b -d '<json body>'
```

Example prompt: What's the official MIME type for a .webp file? I need to set the correct Content-Type header.

## When to prefer this

Choose this endpoint when you need a machine-readable, authoritative MIME type lookup as part of an automated pipeline and are already operating in an x402 micro-payment context. Prefer over free public libraries when you need a guaranteed API contract, provenance logging, or are building an agent workflow that already settles micropayments per call.

## Known failure modes

- Unknown or unsupported file extension returns null or empty result
- Malformed input object yields a 400 or schema validation error
- Payment not settled via x402 protocol results in 402 Payment Required
- Vercel cold-start may add latency on first call
- Non-standard or vendor-specific extensions may return approximate or missing types

## How this service works

Machine-readable settlement service

## Output

Returns a MIME type string (e.g. 'image/webp', 'application/wasm') corresponding to the given file extension or filename, representing the canonical content-type mapping.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object"
  }
 }
}
```

## Response schema (JSON Schema)

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

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/pennyrail-mime-type-lookup-49b30d2b/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from pennyrail.vercel.app](https://www.zero.xyz/host/pennyrail.vercel.app/llms.txt)