{"uid":"cap_2X5m-engdg2xnpO_HZstM","slug":"immuta-seal-on-chain-document-notarization-07e57ea8","name":"Immuta Seal – On-Chain Document Notarization","description":"Notarize a document on-chain: permanent, independently verifiable proof that a SHA-256 hash existed at this moment. Send only the hash - the document never leaves your system. Returns a blockchain transaction receipt.","url":"https://api.immuta.app/seal","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"note":{"type":"string","maxLength":500,"description":"Optional note stored on-chain (up to 500 bytes)"},"label":{"type":"string","maxLength":100,"description":"Short label stored on-chain with the record (1-100 bytes)"},"sha256":{"type":"string","pattern":"^[0-9a-fA-F]{64}$","description":"SHA-256 hash (64 hex chars) of the document to notarize. Compute locally; do not send the document."}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"1","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$1/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"1","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"1","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_hnUpBzlKYv0cbLxatYcuA","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"1","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Notarizes a SHA-256 hash on the blockchain, creating a permanent, independently verifiable timestamp proof that a document existed at a specific moment.","exampleAgentPrompt":"I need to notarize this file — its SHA-256 hash is e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855. Seal it on the blockchain so I have permanent proof it existed right now.","exampleUseCases":[{"title":"Legal contract timestamp proof","prompt":"I've just finalized a contract and need to prove it existed as of today. The SHA-256 hash of the PDF is a665a45920422f9d417e4867efdc4fb8a04a1f3fff1fa07e998e86f7f7a27ae3 — can you seal that on-chain for me?"},{"title":"Intellectual property authorship record","prompt":"I've written a new piece of software and want to establish that I authored it before I file for a patent. The SHA-256 of my source archive is 2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824 — please notarize it on the blockchain right now."},{"title":"Audit trail for compliance evidence","prompt":"We're required to demonstrate that our compliance report wasn't altered after submission. Hash is 9f86d081884c7d659a2feaa0c55ad015a3bf4f1b2b0b822cd15d6c15b0f00a08 — seal it on-chain so we have an immutable timestamped record for our auditors."}],"resultDescription":"Returns a blockchain transaction receipt confirming the hash has been permanently anchored on-chain, including the transaction hash, block number, timestamp, and network details — providing independently verifiable proof that the given SHA-256 hash existed at that exact moment.","failureModes":["Invalid or malformed SHA-256 hash format — returns 400 Bad Request","Insufficient USDC balance or payment failure — transaction not submitted","Blockchain network congestion causing delayed confirmation","Duplicate hash submission — may succeed but creates a second on-chain record","Network timeout before transaction is mined — receipt may not be returned even if transaction was broadcast"],"whenToPreferThis":"Choose this endpoint when you need a cryptographically secure, blockchain-anchored timestamp proving a document or file existed at a specific moment — without ever transmitting the document itself. Ideal for legal evidence, IP authorship records, compliance audit trails, or any workflow requiring tamper-proof, independently verifiable proof of existence. Prefer this over centralized notarization services when trustlessness and decentralization matter.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-13T18:33:02.114Z","isFirstParty":false}