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StampThisFile OpenTimestamps Bitcoin Stamping
x402
StampThisFile OpenTimestamps Bitcoin Stamping is a paid API for AI agents from stampthisfile.com, paid per call via x402, $0.05/call, status unknown (last checked 2026-10-30).
Timestamps one or more SHA-256 file hashes on the Bitcoin blockchain via OpenTimestamps, returning a .ots proof file per hash
Price / call$0.05
Success—
StatusUnknown
How this service works
Timestamp SHA-256 hashes in Bitcoin with OpenTimestamps: returns a standard .ots proof per hash (pending, complete within hours), verifiable without us
Output
For each submitted hash, the endpoint returns a standard OpenTimestamps .ots proof file (initially in 'pending' state, upgraded to a full Bitcoin attestation within hours). The proof is independently verifiable using the open-source OpenTimestamps client without relying on this service. If a webhook URL was provided, a stamps.completed or stamps.failed event is delivered when the Bitcoin confirmation is finalized.
Example use cases
Legal document existence proof
“I need to prove this contract existed before we signed it — its SHA-256 hash is f1e2d3c4b5a6978869504132abcdef9876543210fedcba9876543210fedcba98 — can you anchor it to Bitcoin and get me a .ots proof file?”
Batch media asset notarization
“I have three creative files I need notarized on the blockchain — their SHA-256 hashes are aa11bb22cc33dd44ee55ff66001122334455667788990011aabbccddeeff0011, 1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef, and fedcba9876543210fedcba9876543210fedcba9876543210fedcba9876543210 — please stamp them all and notify my webhook at https://studio.example.com/proofs when done.”
Software release integrity attestation
“Before I publish this software release, I want to timestamp its SHA-256 hash 0a1b2c3d4e5f6a7b8c9d0e1f2a3b4c5d6e7f0a1b2c3d4e5f6a7b8c9d0e1f2a on Bitcoin so users can independently verify it existed at release time — can you do that for me?”
Technical details
Endpoint
POSThttps://stampthisfile.com/v1/stamps?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need a decentralized, independently verifiable timestamp proof anchored to Bitcoin — particularly for legal, compliance, or audit scenarios where you cannot rely on a centralized authority. Ideal for proving document existence before a deadline, notarizing creative works, or attesting software release integrity. Prefer this over centralized timestamping services when the verifier must be able to check the proof without trusting this service at all.
Side effects
- Invalid hash format (not 64 hex characters) returns a validation error
- Exceeding 100 hashes per request returns a 400 error
- Webhook URL unreachable results in stamps.failed event
- Payment failure (insufficient USDC balance) blocks the request
- Bitcoin network congestion may delay confirmation beyond the typical hours window
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| hashes | array | Each hash costs the unit price; send each once |
| webhook | object |
Tags
x402
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