Signed hash receipt API

Issue an HMAC-signed receipt proving the API observed a hash at a specific timestamp.

Price$0.01per request

MethodPOST

Route/v1/trust/notary/receipt

StatusLive

MIME typeapplication/json

Rate limit120/minute

CacheNo cache

trustnotarytimestamphmacreceipt

API URLhttps://x402.hexl.dev/v1/trust/notary/receipt

Integration docs

Example request

{
  "hash": "b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9",
  "algorithm": "sha256"
}

Example response

{
  "receipt": {
    "version": 1,
    "subjectHash": "b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9",
    "algorithm": "sha256",
    "observedAt": "2026-06-03T00:00:00.000Z",
    "nonce": "base64url-nonce",
    "signature": "base64url-signature"
  },
  "provider": "local-hmac-notary"
}

Input schema

{
  "type": "object",
  "required": [
    "hash"
  ],
  "properties": {
    "hash": {
      "type": "string",
      "minLength": 16
    },
    "algorithm": {
      "type": "string",
      "default": "sha256"
    },
    "metadata": {
      "type": "object",
      "additionalProperties": true
    }
  }
}

Output schema

{
  "type": "object",
  "required": [
    "receipt",
    "provider"
  ],
  "properties": {
    "receipt": {
      "type": "object",
      "additionalProperties": true
    },
    "provider": {
      "type": "string"
    }
  }
}