{"uid":"cap_JhX328HufragZjT-XiD8O","slug":"erc20-allowance-lookup-eth-call-f68943f7","name":"ERC20 Allowance Lookup (eth_call)","description":"ERC20 allowance via allowance (eth_call) - how much a spender is approved to move from an owner's wallet","url":"https://api.onesource.io/api/chain/allowance","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET","HEAD","DELETE"],"type":"string"},"queryParams":{"type":"object","required":["contract","owner","spender"],"properties":{"owner":{"type":"string","pattern":"^0x[a-fA-F0-9]{40}$"},"network":{"enum":["ethereum","sepolia","robinhood"],"type":"string","default":"ethereum"},"spender":{"type":"string","pattern":"^0x[a-fA-F0-9]{40}$"},"contract":{"type":"string","pattern":"^0x[a-fA-F0-9]{40}$"}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object","required":["data","meta"],"properties":{"data":{"type":"object","properties":{"name":{"type":"string"},"owner":{"type":"string"},"token":{"type":"string"},"symbol":{"type":"string"},"spender":{"type":"string"},"decimals":{"type":"integer"},"allowance":{"type":"string"}},"description":"Endpoint-specific response payload"},"meta":{"type":"object","required":["endpoint","request_id"],"properties":{"endpoint":{"type":"string"},"cost_usdc":{"type":"string"},"request_id":{"type":"string"},"payment_chain":{"type":"string"},"payment_token":{"type":"string"}}},"error":{"type":["object","null"],"properties":{"code":{"type":"integer"},"message":{"type":"string"}}}}}}}}},"responseSchema":{"type":"json","example":{"data":{"name":"Tether USD","owner":"0xd8da6bf26964af9d7eed9e03e53415d37aa96045","token":"0xdac17f958d2ee523a2206206994597c13d831ec7","symbol":"USDT","spender":"0x6b175474e89094c44da98b954eedeac495271d0f","decimals":6,"allowance":"115792089237316195423570985008687907853269984665640564039457584007913129639935"},"meta":{"endpoint":"/api/chain/allowance","cost_usdc":"0.001","request_id":"00000000abcdef01","payment_chain":"base","payment_token":"USDC"}}},"example":{"request":{"owner":"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045","token":"0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48","network":"ethereum","spender":"0xE592427A0AEce92De3Edee1F18E0157C05861564"},"response":{"data":{"name":"USD Coin","owner":"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045","token":"0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48","symbol":"USDC","spender":"0xE592427A0AEce92De3Edee1F18E0157C05861564","decimals":6,"allowance":"0"},"meta":{"endpoint":"/api/chain/allowance","request_id":"8f42928bfd49c63e"}}},"exampleRequest":{"owner":"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045","token":"0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48","network":"ethereum","spender":"0xE592427A0AEce92De3Edee1F18E0157C05861564"},"tags":["x402"],"displayCostAmount":"0.003","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"settled","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_44c8bbBr-jOTb3nQrV5ov","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":"Returns how many tokens a spender is approved to transfer from an owner's wallet for a given ERC20 token contract on Ethereum or Sepolia.","exampleAgentPrompt":"How much USDC (0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48) is the Uniswap v3 router (0xE592427A0AEce92De3Edee1F18E0157C05861564) approved to spend from my wallet 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045 on Ethereum mainnet?","exampleUseCases":null,"resultDescription":"The approved token allowance — i.e. the maximum number of token units the spender is permitted to transfer from the owner's address — returned as a numeric value in the token's base units (e.g. USDC uses 6 decimals).","failureModes":["Invalid Ethereum address format for owner, spender, or token returns a 400 validation error","Unsupported network value (anything other than 'ethereum' or 'sepolia') returns an error","Token address is not a valid ERC20 contract (no allowance function) may return zero or an RPC error","Network congestion or node unavailability may cause timeouts","Missing required parameter (owner, spender, or token) returns a 422 or 400 error"],"whenToPreferThis":"Use this endpoint when you need to read the current ERC20 token allowance between a specific owner-spender pair on Ethereum mainnet or Sepolia testnet. Ideal for DeFi automation, pre-transaction approval checks, or auditing wallet approvals without needing to run your own Ethereum node. Prefer this over general-purpose RPC providers when you want a simple REST GET interface with x402 micropayment access.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-15T06:42:09.353Z","isFirstParty":false}