{"uid":"cap_gObnbKW7D7pI6XStJ76r6","slug":"keccak-256-hash-ethereum-compatible-a75014bc","name":"Keccak-256 Hash (Ethereum-Compatible)","description":"Landing page para tu negocio en 24 horas: textos, diseño para celular y botón de WhatsApp. Boceto gratis: ves la primera versión antes de pagar. USD 39 de lanzamiento.","url":"https://landingen24h.com/api/x402/util/keccak?utm_source=zero.xyz","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"text":{"type":"string","maxLength":3500,"description":"UTF-8 text, function signature, or hex bytes"},"encoding":{"enum":["utf8","hex"],"type":"string","default":"utf8"}}},"responseSchema":{"type":"json","example":{"note":"Ethereum Keccak-256 (original Keccak padding, not NIST SHA3-256).","encoding":"utf-8","selector":"0xa9059cbb","keccak256":"0xa9059cbb2ab09eb219583f4a59a5d0623ade346d962bcd4e46b11da047c9049b","input_bytes":25}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.001","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":"$0.001/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_erWhrZNwve9x7eze3mSo9","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.001","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Computes the Ethereum-native Keccak-256 hash of a UTF-8 string or hex bytes, returning the full hash and the 4-byte function selector","exampleAgentPrompt":"Hash the function signature 'transfer(address,uint256)' using Ethereum's Keccak-256 (original Keccak padding, not NIST SHA3) so I can get the 4-byte selector — treat it as UTF-8 text.","exampleUseCases":[{"title":"Derive Solidity function selector","prompt":"I need the 4-byte function selector for the ERC-20 'transfer(address,uint256)' function — can you run it through Keccak-256 with UTF-8 encoding and give me the selector?"},{"title":"Hash arbitrary string for Ethereum signing","prompt":"Hash the UTF-8 string 'Hello, Ethereum!' with Keccak-256 using the original Keccak padding (not SHA3-256) and give me the full 32-byte hex digest."},{"title":"Verify ABI encoding from hex bytes","prompt":"I have some hex-encoded bytes '0x7472616e73666572' — can you run them through Keccak-256 with hex encoding and tell me the resulting hash and how many input bytes there were?"}],"resultDescription":"Returns a JSON object with: the full 32-byte keccak256 hex digest, the 4-byte Ethereum function selector (first 4 bytes of hash), the number of input bytes processed, and the encoding used. Also notes that this is original Keccak padding, not NIST SHA3-256.","failureModes":["Input text exceeds 3500 character limit — truncate or split input","Invalid encoding value (must be 'utf8' or 'hex') — defaults to utf8 if omitted","Malformed hex string when encoding is 'hex' — returns error","Empty input string — may return hash of empty byte array","Payment failure via x402 protocol — endpoint returns 402 before processing"],"whenToPreferThis":"Choose this endpoint when you need Ethereum-native Keccak-256 (original Keccak padding), NOT NIST SHA3-256 — the two produce different outputs. Ideal for deriving ERC-20/ERC-721 function selectors, computing event topic hashes, or any Web3 use case requiring the exact Keccak variant used by Ethereum's EVM. Costs only $0.001 USDC per call via x402, making it suitable for on-demand hashing in agent pipelines without running local crypto libraries.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-30T07:03:04.851Z","isFirstParty":false,"canonicalSlug":"keccak-256-hash-ethereum-compatible-a75014bc"}