kairostamp.com v1 verify

https://kairostamp.com/api/v1/verify

answers 402

Receipt verification: read-only hash-chain verification of one existing Kairostamp receipt id. Recomputes the canonical SHA-256 digest, compares it with the stored chain hash, checks linkage to the preceding entry and reports whether the entry is covered by an on-chain checkpoint. Performs no outbound fetch. Single GET query parameter (receipt_id).

We sent a real GET request to this endpoint and it answered 402 with payment requirements we could parse.

Price: $0.005
Network: base-sepolia
Pay to: 0xdB6F694aE695C632C82677a50593B46137808453
Spec dialect: v2 (declares x402Version 2)
Transport: PAYMENT-REQUIRED header
HTTP method: GET
Response latency: 2783 ms
Payment options: 1 usable of 1
Last checked: 2026-09-06T01:19:26.090Z (26d ago)
Category: finance-crypto

Re-check it yourself:
curl "https://api.the402.dev/validate?url=https%3A%2F%2Fkairostamp.com%2Fapi%2Fv1%2Fverify"