{"uid":"cap_2NvOf3tW2v3KuBZFtcfua","slug":"erc-20-allowance-checker-c8771a93","name":"ERC-20 Allowance Checker","description":"How much a spender (router, Permit2, protocol) is approved to move from an owner's ERC-20 balance, with an unlimited-approval flag. Use to check approvals before a swap or to audit risky approvals.","url":"https://bess-x402.onrender.com/v1/evm/allowance?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","DELETE"],"type":"string"},"queryParams":{"type":"object","required":["token","owner","spender"],"properties":{"chain":{"type":"string","description":"ethereum, base, arbitrum, optimism or polygon"},"owner":{"type":"string","description":"Owner address"},"token":{"type":"string","description":"Token address or USDC/USDT/DAI"},"spender":{"type":"string","description":"Spender address"}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":null,"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":"$0.002/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.002","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.002","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_u6naLGAYgP6uN5UWP3mjG","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.002","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Returns how much a spender is approved to move from an owner's ERC-20 token balance, including an unlimited-approval flag, for pre-swap checks or approval audits.","exampleAgentPrompt":"Check how much USDC the Uniswap v3 router (0xE592427A0AEce92De3Edee1F18E0157C05861564) is approved to spend from my wallet 0xAbCd...1234 on Ethereum — and flag if it's an unlimited approval.","exampleUseCases":[{"title":"Pre-swap approval verification","prompt":"Before I swap on Base, can you check if the Uniswap router 0x2626664c2603336E57B271c5C0b26F421741e481 has enough USDC allowance from my wallet 0xMyWallet1234 to cover a $500 trade?"},{"title":"Unlimited approval security audit","prompt":"I want to audit my wallet 0xAbCd5678 on Arbitrum — check if the Permit2 contract 0x000000000022D473030F116dDEE9F6B43aC78BA3 has unlimited approval to spend my DAI."},{"title":"Protocol allowance check before investment","prompt":"Can you look up how much USDT the Aave v3 pool contract 0x87870Bca3F3fD6335C3F4ce8392D69350B4fA4E2 is allowed to move from my address 0xMyWallet9999 on Ethereum?"}],"resultDescription":"Returns the current allowance amount (in token units), whether the approval is unlimited (max uint256), the token symbol, chain, owner, and spender addresses. Useful for determining whether a swap can proceed or whether a potentially dangerous blanket approval exists.","failureModes":["Invalid or non-checksummed token/owner/spender address returns an error","Unsupported chain name returns a validation error","Token address that is not an ERC-20 contract returns an error or zero allowance","Network timeout or RPC node unavailability causes a failed response","Querying a token with no deployed contract on the specified chain returns zero or error"],"whenToPreferThis":"Choose this endpoint when you need a fast, on-chain lookup of ERC-20 spending approvals before executing a swap, bridging, or DeFi interaction, or when auditing a wallet for risky unlimited approvals. It supports major EVM chains (Ethereum, Base, Arbitrum, Optimism, Polygon) and accepts human-readable token symbols like USDC/USDT/DAI in addition to raw addresses.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-29T00:33:29.498Z","isFirstParty":false,"canonicalSlug":"erc-20-allowance-checker-c8771a93"}