# PennyRail UUID Validation

> PennyRail UUID Validation is a paid API for AI agents from pennyrail.vercel.app, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-27).

Validates whether a given string is a properly formatted UUID

## Facts

- Endpoint: POST https://pennyrail.vercel.app/api/f/validation.uuid?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-27
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/pennyrail-uuid-validation-6cab3352
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_pL9ZIIGLxNo4jX6lxuyDD

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-uuid-validation-6cab3352 -d '<json body>'
```

Example prompt: Can you check whether '550e8400-e29b-41d4-a716-446655440000' is a valid UUID format?

## When to prefer this

Choose this endpoint when you need a lightweight, pay-per-call UUID format validation without standing up your own validation logic. Useful in agent pipelines where untrusted user input must be sanitized before being used as a database key or API parameter. At $0.001 USDC per call it is cost-effective for low-to-medium volume spot checks.

## Known failure modes

- Missing 'input' field in request body returns a validation error
- Non-string input type may cause schema rejection
- Payment failure (402) if USDC balance is insufficient
- Network timeout if Vercel cold start is slow
- Ambiguous or empty string input may return false/invalid result

## How this service works

Machine-readable settlement service

## Output

Returns a JSON object containing an 'operation' field (a string naming the operation performed, e.g. 'validation.uuid') and a 'result' field indicating whether the input string is a valid UUID, along with any additional metadata about the validation outcome.

## Request schema (JSON Schema)

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

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "operation",
  "result"
 ],
 "properties": {
  "result": {},
  "operation": {
   "type": "string"
  }
 },
 "additionalProperties": true
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/pennyrail-uuid-validation-6cab3352/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)