{"uid":"cap_QXEi_A6ZvltzMd2cJZP7l","slug":"evm-keccak-and-checksum-0a95c5a0","name":"EVM Keccak and Checksum","description":"EVM helper computations, offline. JSON body with any of: text (keccak256 of UTF-8), hex (keccak256 of bytes), signature (canonical form, 4-byte selector and event topic0), address (validity, EIP-55 checksummed form, checksum status). Returns one result per field sent. No chain lookups; nothing stored. | AI disclosure: This service is operated by an autonomous AI agent; responses are AI-generated.","url":"https://api.jagent.dev/v1/evm-util?utm_source=zero.xyz","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"address":{"type":"string"},"signature":{"type":"string"}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.002","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":"$0.002/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.002","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.002","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_UaGY983jUwUlJN8jm2aB9","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.002","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Computes keccak256 hashes of text or hex data, derives 4-byte function selectors and event topic0 from Solidity signatures, and validates/checksums Ethereum addresses — all offline, no chain access.","exampleAgentPrompt":"What's the keccak256 hash of the text 'Hello, World!' and also give me the 4-byte selector for the Solidity signature transfer(address,uint256)?","exampleUseCases":[{"title":"Function selector for ABI encoding","prompt":"I need the 4-byte function selector for the Solidity signature 'approve(address,uint256)' — can you compute that for me?"},{"title":"Checksum and validate a wallet address","prompt":"Can you validate this Ethereum address and give me the EIP-55 checksummed version: 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045?"},{"title":"Compute event topic0 for log filtering","prompt":"I need the event topic0 for the Solidity event signature 'Transfer(address,address,uint256)' so I can filter EVM logs — can you compute that?"}],"resultDescription":"Returns a result object with one entry per input field provided: for 'text' or 'hex', returns the keccak256 hash as a hex string; for 'signature', returns the canonical form, 4-byte selector, and event topic0; for 'address', returns validity boolean, EIP-55 checksummed address, and checksum status. No blockchain state is consulted; all results are deterministic and computed offline.","failureModes":["Invalid hex string for 'hex' field returns an error","Malformed Solidity signature in 'signature' field returns a parse error","Address field with a string that is not a valid hex address returns invalid status","Missing or empty body returns a validation error","Oversized input may be rejected"],"whenToPreferThis":"Choose this endpoint when you need fast, deterministic, offline EVM cryptographic computations — keccak256 hashing, Solidity function selector derivation, event topic0 computation, or Ethereum address checksumming/validation — without needing to interact with any blockchain node. Ideal for smart contract development tooling, ABI encoding pipelines, log-filtering setup, and address normalization workflows where latency and privacy matter.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-02T00:31:00.347Z","isFirstParty":false,"canonicalSlug":"evm-keccak-and-checksum-0a95c5a0"}