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Akashi Notari Blockchain Proof of Existence
x402
Akashi Notari Blockchain Proof of Existence is a paid API for AI agents from anchor.akashi-notari.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-10).
Records a SHA-256 file hash on the Base blockchain to create an immutable, timestamped proof of existence without uploading the file.
Price / call$0.01
Success—
StatusUnknown
How this service works
Proof of existence for any file. The SHA-256 hash is written on-chain on Base and the block time becomes the proof. The file never leaves its owner.
Output
Returns a JSON object confirming the anchor was recorded, including: the original SHA-256 hash, the Base blockchain transaction hash (txHash), the optional filename, a Unix timestamp of when it was anchored, and a certificateUrl linking to a human-readable certificate page on akashi-notari.com.
Example use cases
Certifying a legal contract timestamp
“I just finalized a contract and need proof it existed before I send it to the other party — anchor the hash 3a7bd3e2360a3d29aa625519ad9dc8b058b7a10e6e3b4f09c1b43f16a7e2df90 on the blockchain and record it as 'service-agreement-2025.pdf'.”
Protecting intellectual property creation date
“I finished my research paper and want to prove I authored it today — please record the SHA-256 hash c0535e4be2b79ffd93291305436bf889314e4a3faec05ecffcbb7df31ad9e51b on Akashi Notari with the filename 'research-paper-final.pdf'.”
Audit trail for compliance documentation
“We need an on-chain timestamp for our compliance report before the quarter closes — can you anchor hash 9f86d081884c7d659a2feaa0c55ad015a3bf4f1b2b0b822cd15d6c15b0f00a8 on Akashi Notari and save it as 'Q4-compliance-report.pdf'?”
Technical details
Endpoint
POSThttps://anchor.akashi-notari.com/anchor?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need a cheap ($0.01 USDC), privacy-preserving, on-chain proof of existence for any file — the file itself is never transmitted, only its hash. Ideal for legal documents, intellectual property, compliance records, or any scenario requiring an immutable timestamp verifiable on Base blockchain. Prefer over centralized notarization services when trustlessness and decentralization matter, and over full-document blockchain storage when privacy is required.
Side effects
- Invalid or malformed SHA-256 hash (not 64 hex characters) returns an error
- Payment failure via x402 protocol prevents anchoring
- Network or RPC issues with Base blockchain cause transaction failure
- Duplicate hash anchoring may succeed but creates a new separate transaction rather than deduplicating
- Filename field too long or containing unsupported characters may be rejected
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| hash | string | SHA-256 of the file, 64 hex characters |
| filename | string | Optional name to record with the hash |
Output
Schema · Response
{
"type": "json",
"example": {
"ok": true,
"hash": "be44340d151cbfa7a5dc59b579dd6632fb0891b573f8fdc927264309a3b168f0",
"txHash": "0xd01d3e019906321b7d410538aebb696dec806df1099756ec85ac7b2da91df7fc",
"filename": "report.pdf",
"timestamp": 1763105659,
"certificateUrl": "https://akashi-notari.com/certificate/?chain=base&hash=0xd01d3e019906321b7d410538aebb696dec806df1099756ec85ac7b2da91df7fc"
}
}Tags
x402
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