Write an on-chain attestation (Ethereum Attestation Service on Base) that binds
Write an on-chain attestation (Ethereum Attestation Service on Base) that binds a call you paid for to the bytes you received: the tool slug, sha256 of the JSON response, the settlement chain and transaction, the payer, the time served and the price, signed by this server's wallet. Give it the settlement transaction from the PAYMENT-RESPONSE (or Payment-Receipt) header of any settled call; the attestation UID and its public page on base.easscan.org come back.
Answeringour last check, 2026-09-24
1 of 1checks answered this week
1117 msmedian answer time
$0.05listed price per call
$0.05price it asked us
Paid test badge: not yet. The checks above are free: we call the tool without paying and read the payment request it sends back. The Verified badge needs paid calls whose answers match the promised output, and nobody can buy a badge.
Endpoint
POST https://agent402.tools/api/attest
| Category | Market data |
|---|---|
| Provider host | agent402.tools |
| Networks | eip155:10, eip155:1329, eip155:137, eip155:143, eip155:42161, eip155:42220, eip155:43114, eip155:4663, eip155:8453 |
| Payment schemes | exact |
| Self-reported calls, 30 days | 38 from 1 payers (the provider's figure, not ours) |
Our checks, last 30 days
| Day | Result | HTTP | Asked | Time |
|---|---|---|---|---|
| 2026-09-24 | valid payment request | 402 | $0.05 | 1117 ms |
Example input (from the provider)
{
"body": {
"tx": "0x2f1fecade9bd945e7817c11e5a34cafe6b349dd8c92a7587efed1de476bddfeb"
},
"bodyType": "json",
"method": "POST",
"type": "http"
}
Promised output schema (from the provider)
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"input": {
"additionalProperties": false,
"properties": {
"body": {
"properties": {
"tx": {
"description": "Settlement transaction of a call you paid for, as carried in that response's PAYMENT-RESPONSE (x402) or Payment-Receipt (MPP) header: EVM hash, Solana or Stellar signature, or Algorand id.",
"type": "string"
}
},
"required": [
"tx"
]
},
"bodyType": {
"enum": [
"json",
"form-data",
"text"
],
"type": "string"
},
"method": {
"enum": [
"POST"
],
"type": "string"
},
"type": {
"const": "http",
"type": "string"
}
},
"required": [
"type",
"method",
"bodyType",
"body"
],
"type": "object"
},
"output": {
"properties": {
"example": {
"properties": {
"attestTx": {
"type": "string"
},
"attestationUrl": {
"type": "string"
},
"attester": {
"type": "string"
},
"block": {
"type": "string"
},
"chain": {
"type": "string"
},
"data": {
"type": "object"
},
"eas": {
"type": "string"
},
"existing": {
"type": "boolean"
},
"schema": {
"type": "string"
},
"schemaUid": {
"type": "string"
},
"uid": {
"type": "string"
},
"verify": {
"type": "object"
}
},
"required": [
"uid",
"attestationUrl",
"attestTx",
"block",
"existing",
"attester",
"chain",
"eas",
"schemaUid",
"schema",
"data",
"verify"
],
"type": "object"
},
"type": {
"type": "string"
}
},
"required": [
"type"
],
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
}