# Cerwal Claim Verifier

> Cerwal Claim Verifier is a paid API for AI agents from cerwal.vercel.app, paid per call via x402, $0.05/call, status unknown (last checked 2026-09-15).

Verifies a claim against web sources by crawling and searching the web, returning a verification result

## Facts

- Endpoint: POST https://cerwal.vercel.app/api/verify
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/cerwal-claim-verifier-9a454086
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_njXvRICg81YuTGU5h_ut9

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 cerwal-claim-verifier-9a454086 -d '<json body>'
```

Example prompt: Can you verify the claim 'SpaceX launched 10 Starlink missions in 2024' using 5 web sources and tell me if it checks out?

## When to prefer this

Choose this endpoint when you need to fact-check or validate a specific textual claim against live web sources, especially when no authentication setup is desired and pay-per-use USDC micropayments via x402 are acceptable. Prefer it over general search APIs when you specifically need a verdict or verification result rather than raw search results.

## Known failure modes

- Claim is too vague or ambiguous for the web to verify
- Insufficient web sources found to validate the claim
- Network timeout while crawling sources
- Invalid or missing 'claim' field returns an error
- Sources parameter set too high causing slow or partial response
- Payment failure via x402 prevents the request from being processed

## How this service works

Web scraping and search for AI agents. No auth, no subscriptions. Pay per request in USDC via x402.

## Output

Returns a JSON object with a 'success' boolean indicating whether verification succeeded and a 'data' object containing the verification result, likely including source findings, supporting or contradicting evidence, and an overall verdict on the claim.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "claim"
 ],
 "properties": {
  "claim": {
   "type": "string",
   "description": "Claim to verify"
  },
  "sources": {
   "type": "number",
   "description": "Number of sources"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "data": {
   "type": "object"
  },
  "success": {
   "type": "boolean"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/cerwal-claim-verifier-9a454086/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from cerwal.vercel.app](https://www.zero.xyz/host/cerwal.vercel.app/llms.txt)