{"slug":"api-x402node-dev-crypto-selector-94e9ef","title":"Compute the 4-byte function/error selector and full keccak topic from a solidity","host":"api.x402node.dev","method":"GET","resource":"https://api.x402node.dev/crypto/selector","category":"market","description":"Compute the 4-byte function/error selector and full keccak topic from a solidity signature, e.g. transfer(address,uint256). For decoding tx input prefixes and matching event topics. function selector, 4byte, method id, event topic, keccak signature Accepts payment on Base or Solana — either network ","price_listed":0.01,"price_asked":null,"state":"effects","state_label":"Not tested: has real-world effects","checks_7d":0,"answered_7d":0,"latency_ms_median":null,"reported_calls_30d":1,"reported_payers_30d":1,"networks":["eip155:8453","solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp"],"badge":"unverified","paid_checks_7d":0,"paid_ok_7d":0,"example_input":{"method":"GET","queryParams":{"signature":"string"},"type":"http"},"output_schema":{"$schema":"https://json-schema.org/draft/2020-12/schema","properties":{"input":{"additionalProperties":false,"properties":{"method":{"enum":["GET"],"type":"string"},"queryParams":{"properties":{"signature":{"description":"canonical signature, e.g. transfer(address,uint256) (required)","type":"string"}},"required":["signature"],"type":"object"},"type":{"const":"http","type":"string"}},"required":["type","method"],"type":"object"}},"required":["input"],"type":"object"},"history":[],"description_full":"Compute the 4-byte function/error selector and full keccak topic from a solidity signature, e.g. transfer(address,uint256). For decoding tx input prefixes and matching event topics. function selector, 4byte, method id, event topic, keccak signature Accepts payment on Base or Solana — either network works.","last_updated":"2026-08-28T07:04:38.638Z","schemes":["exact"]}