{"uid":"cap_Cv54HJNUzXvvnz_MPtFGo","slug":"agentresolver-keccak256-hash-f6f7cdbd","name":"AgentResolver Keccak256 Hash","description":"Verify an x402 endpoint before paying: live payTo, USDC quote, network, asset, resource binding, TLS and endpoint safety for $0.001 on Base or Solana.","url":"https://agentresolver.vercel.app/api/keccak256","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"input":{"type":"string","maxLength":131072},"encoding":{"enum":["utf8","hex"],"type":"string"}}},"responseSchema":{"type":"json","example":{}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.004","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":"$0.004/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.004","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.004","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_a_L20VlTba5E-YZItWtzL","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.004","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 cryptographic hash of an input string, returning the digest as a 0x-prefixed hex value.","exampleAgentPrompt":"Can you compute the keccak256 hash of the string 'Transfer(address,address,uint256)' using utf8 encoding? I need the 0x-prefixed hex digest.","exampleUseCases":[{"title":"EVM Function Selector Generation","prompt":"Hash the string 'transfer(address,uint256)' with keccak256 using utf8 encoding so I can get the 4-byte function selector for my Solidity contract."},{"title":"Ethereum Event Topic Derivation","prompt":"I need the keccak256 hash of 'Transfer(address,address,uint256)' to use as the topic0 filter when querying EVM event logs — please compute it from the utf8 string."},{"title":"Hex-Encoded Data Hashing","prompt":"Compute the keccak256 digest of this hex-encoded payload: '0xdeadbeef' — treat it as hex input and give me the resulting hash."}],"resultDescription":"Returns a JSON object containing: the algorithm name ('keccak256'), the encoding used (utf8 or hex), the number of input bytes processed, and the 32-byte digest as a 0x-prefixed 64-character lowercase hex string (e.g. '0xabc123...').","failureModes":["Missing required 'input' field returns a validation error","Invalid encoding value (not 'utf8' or 'hex') causes a schema error","Malformed hex input when encoding is 'hex' may cause a parsing error","Payment of 0.004 USDC via x402 required; missing payment returns 402 response"],"whenToPreferThis":"Choose this endpoint when you need a pay-per-call, serverless Keccak-256 hash computation — especially for Ethereum/EVM use cases like computing function selectors, event topic hashes, or verifying Solidity keccak256 outputs. Prefer it over running a local library when operating in a sandboxed agent environment without native crypto access. Not suited for SHA-256, MD5, or non-Keccak hashing.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-18T12:44:00.732Z","isFirstParty":false}