{"uid":"cap_ViU2dqfQc10T_cceJ5l1N","slug":"erc-20-token-allowance-checker-f046c736","name":"ERC-20 Token Allowance Checker","description":"Check an ERC-20 token approval on base, ethereum, arbitrum, optimism, polygon, bsc: how much a spender (router, Permit2, contract) may move from an owner's wallet, whether the approval is unlimited, and whether it covers the owner's full balance.","url":"https://dt0ur.online/api/onchain/allowance?utm_source=zero.xyz","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"chain":{"enum":["base","ethereum","arbitrum","optimism","polygon","bsc"],"type":"string","default":"base","description":"EVM chain: base, ethereum, arbitrum, optimism, polygon, bsc (default base)"},"owner":{"type":"string","description":"Wallet that granted the approval"},"token":{"type":"string","description":"ERC-20 contract address"},"spender":{"type":"string","description":"Approved spender (e.g. router or Permit2)"}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.01","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":"$0.01/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_eiTYxaF4Eoh_eKOPKcpTe","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.01","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Checks how much a spender (router, Permit2, contract) is approved to move from an owner's wallet for a given ERC-20 token on major EVM chains, including whether the approval is unlimited or covers the full balance.","exampleAgentPrompt":"Check how much allowance the Uniswap v3 router (0xE592427A0AEce92De3Edee1F18E0157C05861564) has to spend my USDC (0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48) from my wallet 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045 on Ethereum.","exampleUseCases":[{"title":"DeFi swap safety check","prompt":"Before I execute this Uniswap swap on Base, can you check whether the router 0x2626664c2603336E57B271c5C0b26F421741e481 already has enough allowance to spend my USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) from my wallet 0xAb5801a7D398351b8bE11C439e05C5B3259aec9B?"},{"title":"Unlimited approval risk audit","prompt":"I want to know if I accidentally gave unlimited token approval to some contract — check the allowance that 0x1111111254EEB25477B68fb85Ed929f73A960582 has on my WETH (0x4200000000000000000000000000000000000006) on Optimism for wallet 0x70997970C51812dc3A010C7d01b50e0d17dc79C8, and flag if it's unlimited."},{"title":"Cross-chain allowance monitoring","prompt":"Can you check the Permit2 contract allowance (0x000000000022D473030F116dDEE9F6B43aC78BA3) for my ARB token (0x912CE59144191C1204E64559FE8253a0e49E6548) on Arbitrum for my wallet 0x3C44CdDdB6a900fa2b585dd299e03d12FA4293BC, and tell me whether it covers my full balance?"}],"resultDescription":"Returns the allowance amount the spender is permitted to transfer, a flag indicating whether the approval is set to the unlimited (max uint256) value, and whether the approved amount covers the owner's current token balance on the specified EVM chain.","failureModes":["Invalid or non-checksummed wallet/token/spender address returns an error","Unsupported chain value returns a validation error","Token address is not a valid ERC-20 contract on the specified chain","Network RPC issues may cause timeouts or failures","Zero allowance returned if no approval has been granted"],"whenToPreferThis":"Use this endpoint when you need to verify ERC-20 token approval state on any of the six supported EVM chains (Base, Ethereum, Arbitrum, Optimism, Polygon, BSC) before executing DeFi transactions, auditing wallet permissions, or checking for risky unlimited approvals — particularly useful in agentic DeFi workflows where approval status must be confirmed before submitting swaps or transfers.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-01T00:48:08.563Z","isFirstParty":false,"canonicalSlug":"erc-20-token-allowance-checker-f046c736"}