{"uid":"cap_R2NFhl3mPbQ5lh2zaTpbO","slug":"signalharness-eip-712-typed-data-hash-9d439701","name":"SignalHarness EIP-712 Typed Data Hash","description":"Explore 330 pay-per-call x402 API services and 27 agent-native digital products, with Base USDC pricing, secure Polar checkout, and free discovery.","url":"https://signalharness.ai/api/agent/services/typed_data_hash_eip712/invoke","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"typed_data_hash_request":{"type":"string","maxLength":65536,"minLength":2}}},"responseSchema":{"type":"json","example":{"replay":false,"result":{"warnings":["Hashing does not sign, submit, or validate application intent."],"service_id":"typed_data_hash_eip712","evidence_scope":"caller_supplied_data","typed_data_hash":"{\"hash\":\"0x8db8c5ec3114da2288a018bc3f8bae3e5e0ef77c3848832fe9adbea12c047e1b\",\"primary_type\":\"Note\"}"},"status":"succeeded","receipt":{"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","usage":[],"status":"succeeded","network":"eip155:8453","artifacts":[],"endedAtMs":0,"latencyMs":0,"paymentId":"example-payment","receiptId":"example-receipt","requestId":"example-request","serviceId":"typed_data_hash_eip712","executionId":"example-execution","startedAtMs":0,"amountAtomic":"10000","resultSha256":"76ea22f78bfba3dcbd2a4b5f3273c9ff5a2e045f87018ad4f2fe487745d9106a","serviceVersion":"1.0.0","settlementReference":"0x0000000000000000000000000000000000000000000000000000000000000000"},"artifacts":[],"requestId":"example-request","executionId":"example-execution"}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.01","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":"$0.01/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_M14HWgShSmghIiTIBY6Yv","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.01","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Computes the EIP-712 typed data hash for a given structured data input, returning the canonical hash used for Ethereum typed structured data signing.","exampleAgentPrompt":"Can you compute the EIP-712 typed data hash for this structured data payload I need to sign on Ethereum? Here's the typed data JSON: {\"domain\":{\"name\":\"MyApp\",\"version\":\"1\",\"chainId\":1},\"types\":{\"Mail\":[{\"name\":\"from\",\"type\":\"address\"},{\"name\":\"to\",\"type\":\"address\"},{\"name\":\"contents\",\"type\":\"string\"}]},\"message\":{\"from\":\"0xabc...\",\"to\":\"0xdef...\",\"contents\":\"Hello!\"}}","exampleUseCases":[{"title":"Sign typed permit for DeFi transaction","prompt":"I need to sign a Unipermit typed data message for a token approval — can you compute the EIP-712 hash for this payload before I send it to my wallet for signing? Here's the typed data: {\"domain\":{\"name\":\"Uniswap\",\"chainId\":1},\"types\":{\"Permit\":[{\"name\":\"owner\",\"type\":\"address\"},{\"name\":\"value\",\"type\":\"uint256\"}]},\"message\":{\"owner\":\"0x123...\",\"value\":\"1000000\"}}"},{"title":"Validate EIP-712 hash before contract submission","prompt":"Before I submit this typed data to my smart contract, can you compute the EIP-712 hash so I can double-check it matches what my contract expects? My typed data is: {\"domain\":{\"name\":\"VaultProtocol\",\"version\":\"2\",\"chainId\":8453},\"types\":{\"Withdraw\":[{\"name\":\"amount\",\"type\":\"uint256\"},{\"name\":\"nonce\",\"type\":\"uint256\"}]},\"message\":{\"amount\":\"500000000\",\"nonce\":\"3\"}}"},{"title":"Debug signature mismatch in dApp","prompt":"My dApp is producing a signature mismatch — can you compute the EIP-712 typed data hash for this payload so I can see if the hash my frontend generates matches? Here's the typed data object: {\"domain\":{\"name\":\"MyNFT\",\"version\":\"1\",\"chainId\":137},\"types\":{\"Mint\":[{\"name\":\"to\",\"type\":\"address\"},{\"name\":\"tokenId\",\"type\":\"uint256\"}]},\"message\":{\"to\":\"0xabc...\",\"tokenId\":\"42\"}}"}],"resultDescription":"Returns a JSON object containing the computed EIP-712 typed data hash (as a hex string), any warnings about the input data, the evidence scope indicating the data was caller-supplied, and the service ID. Also includes a full receipt with payment details, network, execution timing, request/execution IDs, and a SHA-256 of the result for auditability.","failureModes":["Invalid or malformed typed data JSON returns an error","Typed data exceeding 65536 characters is rejected","Missing required EIP-712 fields (domain, types, message) causes failure","Input shorter than 2 characters is rejected by schema validation","Network or payment failure returns a failed status in the receipt"],"whenToPreferThis":"Use this endpoint when you need a reliable, pay-per-use EIP-712 typed data hash computation without running your own Ethereum tooling or library. Particularly useful for AI agents operating in blockchain workflows that need to compute or verify EIP-712 hashes on demand without setting up ethers.js or viem locally. Prefer this over generic hashing APIs when you specifically need EIP-712 structured data encoding semantics.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-13T13:07:12.958Z","isFirstParty":false}