{"uid":"cap_jvCWM5Q5rOIclCp8Za8xW","slug":"keccak-256-hash-calculator-9d17acc2","name":"Keccak-256 Hash Calculator","description":"Keccak hash, keccak256. Keccak-256 hash (the Ethereum hash) of text or of 0x hex bytes, as used for function selectors, event topics and storage slots. Use when building or decoding EVM calls.","url":"https://agent-data-tools.revmesh2074.workers.dev/keccak?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET"],"type":"string"},"queryParams":{"type":"object","required":["text"],"properties":{"text":{"type":"string","examples":["transfer(address,uint256)"],"description":"Text, or 0x-prefixed hex bytes, up to 10,000 characters"}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object","properties":{"input":{"type":"string"},"selector":{"type":"string"},"inputType":{"type":"string"},"keccak256":{"type":"string"}}}}}}},"responseSchema":{"type":"json","example":{"input":"transfer(address,uint256)","selector":"0xa9059cbb","inputType":"text","keccak256":"0xa9059cbb2ab09eb219583f4a59a5d0623ade346d962bcd4e46b11da047c9049b"}},"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_x409umAAKm4EPVmJQZtEQ","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 Keccak-256 hash of a text string or hex bytes, returning the hash and the first 4-byte function selector","exampleAgentPrompt":"What's the keccak256 hash and 4-byte function selector for the Solidity signature transfer(address,uint256)?","exampleUseCases":[{"title":"Derive Solidity function selector","prompt":"What is the 4-byte function selector for the ERC-20 approve(address,uint256) function? I need the keccak256 hash to verify it matches what's in my contract ABI."},{"title":"Compute event topic hash","prompt":"Can you give me the keccak256 hash of the Solidity event signature Transfer(address,address,uint256)? I need the topic0 value so I can filter Ethereum logs for ERC-20 transfers."},{"title":"Hash arbitrary text or hex data","prompt":"Compute the keccak256 hash of the text 'Hello, world!' for me — I want to verify it matches the hash I computed locally."}],"resultDescription":"A JSON object containing the original input string, the input type (text or hex), the 4-byte function selector (first 4 bytes of the hash, 0x-prefixed), and the full 32-byte keccak256 hash as a 0x-prefixed hex string.","failureModes":["Input text exceeds 10,000 characters — request rejected","Missing required 'text' query parameter — returns error","Invalid 0x-prefixed hex that is malformed — may return error or hash raw bytes","Payment not received — call is not charged and returns 402"],"whenToPreferThis":"Use this endpoint when you need to compute a Keccak-256 hash on-demand without setting up a local library, particularly for deriving Ethereum/Solidity function selectors and event topic hashes. Ideal for AI agents working with smart contract ABIs, log filtering, or verifying on-chain data. No API key required; pay $0.001 USDC per call via x402.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-11-05T18:35:25.280Z","isFirstParty":false,"canonicalSlug":"keccak-256-hash-calculator-9d17acc2"}