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KHOTEM Attest — Notary & Session Verification
x402
KHOTEM Attest — Notary & Session Verification is a paid API for AI agents from khotem.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-15).
Looks up and attests a transaction hash, SHA-256 digest, or timestamp stamp via a SEAL notary audit, paid with USDC on Base.
Price / call$0.02
Success—
StatusUnknown
How this service works
Paid cryptographic witness services for autonomous agents and humans: seals, attestations, verification, audit, sealed document thread. x402-native micropayments, USDC on Base / Polygon / Solana, direct on-chain verification. No accounts, no API keys, no KYC.
Output
Returns the attestation or notary audit result for the given reference — including whether the hash, transaction, or stamp has a valid SEAL record, along with any associated timestamp and notary metadata.
Example use cases
Verify signed document hash
“I just received a signed contract and the sender gave me this SHA-256 hash — can you check the KHOTEM notary to confirm it's been attested: b94d27b9934d3e08a52e52d7da7dabfac484efe04294e576f3d0d4c9f9b3e1a2?”
Audit a blockchain transaction seal
“We processed a payment and I need to confirm the transaction was notarized — can you look up this tx hash in KHOTEM to get the audit record: 0xabc123def456789abcdef1234567890abcdef1234567890abcdef1234567890ab?”
Confirm timestamp stamp authenticity
“I have a stamp ID from a session event and I need to verify it's legitimate in the KHOTEM notary system — please look it up: STAMP-20240601-XK9P2QR.”
Technical details
Endpoint
POSThttps://khotem.com/api/attestWhen to prefer
Use this endpoint when you need a lightweight, no-signup, pay-per-call notary lookup for transaction hashes, SHA-256 document digests, or session stamps on the Base blockchain. It is ideal for agents that need instant cryptographic attestation without any identity verification or registration overhead. Prefer it over traditional notary services when cost-per-call ($0.02 USDC) and permissionless access matter.
Side effects
- Reference not found in notary — returns not-found or null attestation
- Invalid format for ref (not a valid txHash, SHA-256, or stamp) — returns validation error
- Payment failure on Base network — call not processed
- Network timeout or upstream SEAL notary unavailable — returns service error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| refrequired | string | txHash (0x+64 hex) / sha256 (64 hex) / stamp (16 hex) — exact match |
Output
Schema · Response
{
"entry": {
"ts": "2026-08-24T12:00:00.000Z",
"event": "seal",
"sha256": "e3b0c4…"
},
"attest": "CONFIRMED",
"attest_seal": "a1b2c3d4e5f60708",
"payment_seal": "1020304050607080"
}Tags
x402
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