# PayAI Attestation Verifier

> PayAI Attestation Verifier is a paid API for AI agents from payai.agentstools.dev, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Verifies an EIP-712 or EAS off-chain attestation produced by /notarize, recovering the signer and checking integrity without any network calls or key material.

## Facts

- Endpoint: POST https://payai.agentstools.dev/attest/verify
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/payai-attestation-verifier-8c7d8219
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_dq6PjzaiOPRgewuAGptQz

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 payai-attestation-verifier-8c7d8219 -d '<json body>'
```

Example prompt: Can you verify this EAS off-chain attestation I got back from /notarize — check whether the signer matches the expected attestor, whether the EAS UID recomputes correctly, and if I give you the original request body, confirm its sha256 matches the attested hash?

## When to prefer this

Use this endpoint when you need to cryptographically verify an attestation issued by the PayAI notarize service (/notarize) without making any external network calls or requiring private keys — ideal for pure offline integrity checks of EIP-712 or EAS off-chain attestations, including optional payload hash verification.

## Known failure modes

- Invalid or malformed attestation object causes a validation error
- Signature recovery fails if the attestation was tampered with
- EAS UID mismatch reported if attestation fields have been altered
- sha256 mismatch if payload_base64 does not correspond to the attested body
- Wrong attestation type (not eip712 or eas_offchain) causes rejection

## How this service works

Verify an attestation produced by /notarize (either the EIP-712 or the EAS off-chain form) — pure compute, no network and no keys. Recovers the signer and reports whether it matches this service's attestor, whether the EAS UID recomputes, and (if you supply the original body as payload_base64) whether its sha256 matches the attested hash.

## Output

Returns the recovered signer address, whether it matches the service's known attestor, whether the EAS UID recomputes to the expected value, and (if payload_base64 was supplied) whether the sha256 of the decoded payload matches the hash embedded in the attestation.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "attestation": {
   "type": "object",
   "description": "An attestation object from /notarize (eip712 or eas_offchain form)"
  },
  "payload_base64": {
   "type": "string",
   "description": "Optional: base64 of the original body to re-hash against the attested sha256"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/payai-attestation-verifier-8c7d8219/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from payai.agentstools.dev](https://www.zero.xyz/host/payai.agentstools.dev/llms.txt)