{"slug":"api-eucompliance-tools-x402-token-35191e","title":"Pre-flight check before a swap or transfer","host":"api.eucompliance.tools","method":"GET","resource":"https://api.eucompliance.tools/x402/token","category":"market","description":"Pre-flight check before a swap or transfer: ERC-20 allowance, balance, decimals and symbol in one call, read live from the chain at the latest block. Pass an amount and get a straight would_succeed verdict with the blocking reason and the action needed. Base, Ethereum, Arbitrum, Optimism, Polygon. A","price_listed":0.002,"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":["eip155:137","eip155:42161","eip155:8453","solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp"],"badge":"unverified","paid_checks_7d":0,"paid_ok_7d":0,"example_input":{"method":"GET","queryParams":{"amount":25,"chain":"base","owner":"0x0000000000000000000000000000000000000001","spender":"0x0000000000000000000000000000000000000002","token":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"},"type":"http"},"output_schema":{"$schema":"https://json-schema.org/draft/2020-12/schema","properties":{"input":{"additionalProperties":false,"properties":{"method":{"enum":["GET","HEAD","DELETE"],"type":"string"},"queryParams":{"properties":{"amount":{"description":"amount you intend to move, optional - returns a would_succeed verdict","type":"number"},"chain":{"enum":["base","ethereum","arbitrum","optimism","polygon"],"type":"string"},"owner":{"description":"wallet holding the tokens","type":"string"},"spender":{"description":"contract that would spend them, optional","type":"string"},"token":{"description":"ERC-20 contract address","type":"string"}},"required":["token","owner"],"type":"object"},"type":{"const":"http","type":"string"}},"required":["type","method"],"type":"object"}},"required":["input"],"type":"object"},"history":[],"description_full":"Pre-flight check before a swap or transfer: ERC-20 allowance, balance, decimals and symbol in one call, read live from the chain at the latest block. Pass an amount and get a straight would_succeed verdict with the blocking reason and the action needed. Base, Ethereum, Arbitrum, Optimism, Polygon. A missing approval burns the gas of a failed transaction - this call costs a fraction of that.","last_updated":"2026-08-27T15:05:46.926Z","schemes":["exact"]}