{"uid":"cap_fI8kQohWPCGNmlkIzQ68l","slug":"erc-20-token-allowance-lookup-40c1cd58","name":"ERC-20 Token Allowance Lookup","description":"558 pay-per-call data APIs for AI agents: Solana and EVM on-chain data, tokenized stocks, DeFi, Hyperliquid, economy and official statistics, FX, validation, web and developer tools. Pay in USDC via x402.","url":"https://api.vextorium.com/v1/token-allowance?utm_source=zero.xyz","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"owner":{"type":"string","description":"Owner wallet address"},"token":{"type":"string","description":"Token contract address"},"network":{"enum":["base","ethereum","arbitrum","optimism","polygon"],"type":"string","description":"EVM network (default base)"},"spender":{"type":"string","description":"Spender (contract) address"}}},"responseSchema":{"type":"json","example":{"note":null,"owner":"0xb9f06D2734B7E9D7b21B64C4D8b95bd774b71aCf","token":"USDC","network":"base","spender":"0x3d4e44Eb1374240CE5F1B871ab261CD16335B76a","contract":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unlimited":false,"permission":0}},"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":"$0.003/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_LmWyRn_U6Pj8JK2DRLn_j","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 move from an owner's wallet on a given EVM network, flagging whether the approval is unlimited.","exampleAgentPrompt":"Check the USDC allowance on Base for owner wallet 0xb9f06D2734B7E9D7b21B64C4D8b95bd774b71aCf and spender 0x3d4e44Eb1374240CE5F1B871ab261CD16335B76a — I want to know if it's unlimited or the exact amount approved.","exampleUseCases":[{"title":"Wallet security audit for risky approvals","prompt":"Scan my wallet 0xb9f06D2734B7E9D7b21B64C4D8b95bd774b71aCf on Ethereum — check whether the Uniswap router 0x68b3465833fb72A70ecDF485E0e4C7bD8665Fc45 has an unlimited approval on my USDC tokens."},{"title":"Pre-transaction allowance verification","prompt":"Before I submit a swap on Arbitrum, check if contract 0x1b02dA8Cb0d097eB8D57A175b88c7D8b47997506 already has enough WETH allowance from my wallet 0xabc123...def456 to cover a 2 WETH trade."},{"title":"DeFi protocol approval monitoring","prompt":"I want to know how much DAI the Aave lending pool contract 0x794a61358D6845594F94dc1DB02A252b5b4814aD is allowed to move from wallet 0xdef789...abc012 on Polygon — flag it if it's set to unlimited."}],"resultDescription":"Returns a JSON object with the token symbol, contract address, network, owner and spender addresses, the numeric allowance (permission), and a boolean 'unlimited' flag indicating whether the approval is set to the maximum uint256 value. Also includes an optional note field.","failureModes":["Invalid or malformed wallet/contract addresses return an error","Unsupported network returns a validation error","Token contract address not found on the specified network may return null values","RPC node timeout causes a failed lookup","Missing required fields (token, owner, spender) returns a schema validation error"],"whenToPreferThis":"Use this endpoint when you need a fast, single on-chain read of an ERC-20 allowance without running your own blockchain node or writing contract call code. It is ideal for wallet security dashboards, pre-swap checks, and approval auditing workflows across Base, Ethereum, Arbitrum, Optimism, and Polygon. Prefer this over general-purpose blockchain RPC tools when you specifically need the allowance amount and an explicit unlimited-approval flag in a structured JSON response.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-19T12:45:40.668Z","isFirstParty":false,"canonicalSlug":"erc-20-token-allowance-lookup-40c1cd58"}