# ProofAudit.ai Canonical Hash Verification

> ProofAudit.ai Canonical Hash Verification is a paid API for AI agents from proofaudit.ai, paid per call via x402, $0.025/call, status unknown (last checked 2026-10-17).

Returns a sealed SHA-256 canonical hash and protocol token for ProofAudit.ai, verifying the service identity on the Base network for audit chain-of-custody purposes.

## Facts

- Endpoint: GET https://proofaudit.ai/api/x402/canonical-hash?utm_source=zero.xyz
- Price: $0.025/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-17
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/proofaudit-ai-canonical-hash-verification-e1b1bcb7
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_-SDGuzBMuiqBcjI-sLuZU

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 proofaudit-ai-canonical-hash-verification-e1b1bcb7
```

Example prompt: Can you verify the canonical identity of ProofAudit.ai and give me the sealed SHA-256 hash and protocol token address on Base so I can confirm the service is genuine before attaching its audit receipts to my compliance report?

## When to prefer this

Use this endpoint when you need to establish chain-of-custody proof or verify the on-chain identity of ProofAudit.ai before trusting its audit evidence packs. Prefer this over general blockchain lookups when you specifically need the sealed canonical hash and protocol token for compliance workflows involving ProofAudit.ai.

## Known failure modes

- Service unavailable or payment not processed — returns non-200 status with no JSON body
- Payment insufficient — x402 payment rejection before endpoint is reached
- verified field returns false — service identity could not be confirmed at time of call
- Stale or mismatched hash — hash differs from previously cached value, suggesting a service update or potential tampering

## How this service works

Capture, verify, approve, and export audit-ready evidence packs for credit, compliance, and financial operations.

## Output

A JSON object containing: service name ('ProofAudit.ai'), ticker ('PROOF'), network ('base'), a success and verified boolean flag, a sealed SHA-256 hash string (e.g. 'PROOF-87B43B8DEB11505A'), the protocol token contract address on Base, and a URL to the nodes portal.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input",
  "output"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "POST"
     ],
     "type": "string"
    },
    "headers": {
     "type": "object",
     "additionalProperties": {
      "type": "string"
     }
    },
    "queryParams": {
     "type": "object",
     "additionalProperties": {
      "type": "string"
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type",
    "example"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ticker": "PROOF",
  "network": "base",
  "service": "ProofAudit.ai",
  "success": true,
  "verified": true,
  "nodesPortal": "https://proofaudit.ai/nodes",
  "sealedSha256": "PROOF-87B43B8DEB11505A",
  "protocolToken": "0x87b43b8dEb11505ADc6898899961d6d419CaBB07"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/proofaudit-ai-canonical-hash-verification-e1b1bcb7/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from proofaudit.ai](https://www.zero.xyz/host/proofaudit.ai/llms.txt)