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api.fairseal.io v1 notarize
https://api.fairseal.io/v1/notarize
answers 402
Anchor an AI agent decision or audit record to Base mainnet. Submit {schema, payload_hash (SHA-256 hex, 64 chars), metadata}; service queues into a Merkle batch and returns a receipt with pending_anchor status immediately. Full Merkle proof and on-chain anchor_tx available via free GET /v1/notarize/:receipt_id after batch anchors (within batch_threshold receipts or 120s).
We sent a real
POST request to this endpoint and it
answered 402 with payment requirements we could parse.
- Price
- $0.02
- Network
- base
- Pay to
- 0xBd5eB5559f5Ac14475AC0C81b6735A4d9106ce28
- Spec dialect
- v2 (declares x402Version 2)
- Transport
- PAYMENT-REQUIRED header
- HTTP method
- POST
- Response latency
- 638 ms
- Payment options
- 2 usable of 2
- Last checked
- 2026-09-06T01:22:47.062Z (2h ago)
- Category
- finance-crypto
Re-check it yourself:
curl "https://api.the402.dev/validate?url=https%3A%2F%2Fapi.fairseal.io%2Fv1%2Fnotarize"