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KHOTEM Seal — Content Notarization & Audit
x402
KHOTEM Seal — Content Notarization & Audit is a paid API for AI agents from khotem.com, paid per call via x402, $0.05/call, status unknown (last checked 2026-09-14).
Cryptographically seals and notarizes content or a pre-computed SHA-256 hash, creating a verifiable timestamped record for audit purposes, paid instantly via USDC on Base.
Price / call$0.05
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
A seal certificate or notarization record containing the timestamped cryptographic proof of the content or hash, suitable for audit trails and verifying that content existed and was unchanged at the time of sealing.
Example use cases
Contract text timestamping for freelancers
“I just finalized a freelance agreement and need a tamper-proof notarized seal on this text: 'Service agreement between PixelWorks Studio and Client MNO Inc, effective 2025-06-01, scope: logo design for $2,500.' Can you seal it so I have a verifiable record?”
Software release integrity proof
“I have the SHA-256 hash of our v2.4.1 release binary — it's 'a3f8c2d1e9b0456789abcdef1234567890abcdef1234567890abcdef12345678'. Please notarize that hash so we can prove the build existed and was unchanged at this moment.”
Legal document audit trail
“Seal the following NDA excerpt for audit purposes so we can prove it wasn't altered: 'Both parties agree to keep all disclosed information confidential for a period of five years from the signing date.' I need a timestamped cryptographic proof.”
Technical details
Endpoint
POSThttps://khotem.com/api/sealWhen to prefer
Choose this endpoint when you need a lightweight, no-signup, pay-per-use cryptographic notarization of content or a hash — particularly when KYC-free instant payment via USDC on Base is desirable and you want a per-call audit record without a subscription or account setup.
Side effects
- Missing both 'hash' and 'content' fields — endpoint requires at least one
- Invalid SHA-256 hash format — must be a valid 64-character hex string
- Payment failure — insufficient USDC balance or Base network issues
- Network timeout during seal creation
- Duplicate seal submission may create a new record rather than returning the existing one
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| hash | string | Pre-computed sha256 hex (64 chars) |
| content | string | Content to hash and seal |
Output
Schema · Response
{
"note": "content not stored: hashed and forgotten",
"proof": "recorded in the KHOTEM ledger; verifiable via /api/attest",
"sha256": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
"witness": "KHOTEM-SEAL",
"timestamp": "2026-08-24T12:00:00.000Z",
"seal_stamp": "a1b2c3d4e5f60708",
"payment_seal": "1020304050607080"
}Tags
x402
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