{"uid":"cap_H0d4-RA4PCv4OHMOgPQ7C","slug":"swift-bot-labs-evm-function-selector-calculator-e1ae5898","name":"Swift Bot Labs EVM Function Selector Calculator","description":"62 small, deterministic utility APIs (DNS and e-mail checks, web extraction, EVM decoding, x402 checks, IP math, JSON/CSV, hashing, conversions). No account or API key: pay per call in USDC with x402.","url":"https://x402-toolbox.swiftbotlab.workers.dev/v1/evm/selector?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","HEAD"],"type":"string"},"headers":{"type":"object","additionalProperties":{"type":"string"}},"queryParams":{"type":"object","required":["signature"],"properties":{"signature":{"type":"string","description":"e.g. transfer(address to, uint256 amount)"}},"additionalProperties":false},"discoverable":{"type":"boolean"}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":{"type":"json","example":{"ok":true,"tool":"evm-selector","result":{"topic":"0x...","selector":"0xa9059cbb","canonical":"transfer(address,uint256)"}}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.003","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":"$0.003/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.003","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.003","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_V3nEjL4J0UEDoTcC4hkjJ","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.003","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Computes the 4-byte EVM function selector and 32-byte topic hash from a Solidity function signature string","exampleAgentPrompt":"What's the 4-byte EVM function selector and topic hash for the Solidity function signature transfer(address,uint256)?","exampleUseCases":[{"title":"Decode unknown calldata in transaction","prompt":"I'm looking at an Ethereum transaction and the calldata starts with 0xa9059cbb — can you tell me what the selector and canonical signature are for transfer(address,uint256) so I can confirm it matches?"},{"title":"Build smart contract ABI tooling","prompt":"I'm writing a script that needs the 4-byte selector and keccak256 topic hash for the Solidity function approve(address,uint256) — can you compute those for me?"},{"title":"Verify event topic hash for log filtering","prompt":"I need to filter Ethereum logs for Transfer events. What's the 32-byte topic hash and selector for Transfer(address,address,uint256) so I can set up the right filter?"}],"resultDescription":"A JSON object with ok:true, the tool name 'evm-selector', and a result containing the 4-byte hex function selector (e.g. 0xa9059cbb), the 32-byte keccak256 topic hash (0x...), and the canonical normalized form of the input signature.","failureModes":["Invalid or malformed Solidity signature string returns an error","Missing required 'signature' query parameter returns a validation error","Payment failure or insufficient USDC balance blocks the call with a 402 response","Ambiguous or non-canonical type names may produce unexpected selectors"],"whenToPreferThis":"Use this endpoint when you need a fast, deterministic, pay-per-call computation of an EVM function selector or topic hash without setting up an account or SDK. Ideal for one-off lookups in agent workflows or scripts that occasionally need ABI encoding without a full Ethereum node or library dependency.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-31T18:41:27.272Z","isFirstParty":false,"canonicalSlug":"swift-bot-labs-evm-function-selector-calculator-e1ae5898"}