IOTA Notarization (Proof of Existence)

Proof of existence on the IOTA mainnet: send text, a SHA-256 hash or a URL and get a tamper-proof timestamp. We store only the SHA-256 (never your content) in a locked notarization of the official IOTA Notarization package: it cannot be changed or transferred and its deletion is locked until 2106. Returns object id, transaction digest, ledger time and explorer links. Use for contracts, invoices, AI outputs, datasets, web page evidence or audit logs. Check later with iota-verify. Network fee included.

Run free trial ↗3 free calls per day with the example input. Paid: $0.010 USDC, no limit.

Call it

import { wrapFetchWithPayment, x402Client } from "@x402/fetch";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

const client = new x402Client();
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.EVM_PRIVATE_KEY) });
const payFetch = wrapFetchWithPayment(fetch, client);

const res = await payFetch("https://agentsvc.io/api/v1/proxy/iota-notarize", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({"text":"Invoice 2026-1042, total 1,250.00 EUR, issued 2026-10-11"}),
});
const { data, payment } = await res.json();  // payment.status "settling"; header X-Payment-Settle: sync returns payment.transaction

Input

Field	Type	Description
text	string	Content to notarize (hashed with SHA-256, max 1 MB)
hash	string	SHA-256 hex of your file, alternative to text
url	string	Notarize the exact bytes this URL returns now (max 20 MB)
label	string	Optional public label stored with the proof, max 120 chars

Output

Field	Type	Description
proof	object
sha256	string
immutable	boolean
explorer	object