{"uid":"cap_HbP_aeDruaH7NWpdxGkIL","slug":"xerxes-erc20-allowance-lookup-804ad897","name":"Xerxes ERC20 Allowance Lookup","description":"Returns the amount of ERC-20 tokens that a spender is allowed to withdraw from an owner's account. Provide token (ERC-20 contract address), owner (owner address), and spender (spender address). Query: token (ERC-20 contract, 0x + 40 hex), owner (0x + 40 hex), spender (0x + 40 hex).","url":"https://ari001.tailb4ac3a.ts.net/v1/ventures/ethereum_contract_abi_service/erc20_allowance?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET","HEAD","DELETE"],"type":"string"},"queryParams":{"type":"object","required":["token","owner","spender"],"properties":{"owner":{"type":"string","pattern":"^0x[a-fA-F0-9]{40}$","description":"0x + 40 hex"},"token":{"type":"string","pattern":"^0x[a-fA-F0-9]{40}$","description":"ERC-20 contract, 0x + 40 hex"},"spender":{"type":"string","pattern":"^0x[a-fA-F0-9]{40}$","description":"0x + 40 hex"}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object","required":["ok","service"],"properties":{"ok":{"type":"boolean"},"chain":{"type":"string"},"error":{"type":"string","description":"present when ok is false"},"method":{"type":"string"},"result":{"type":"string","description":"the uint256 as a decimal string"},"service":{"type":"string"}}}}}}},"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":"$0.003/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_0h1bxf3_g-Csr_BIoSsIX","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 the uint256 allowance amount that a spender is approved to withdraw from an ERC20 token owner's account on Ethereum mainnet.","exampleAgentPrompt":"What's the current allowance that Uniswap's router (0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D) is approved to spend from 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045's USDC (0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48) holdings on Ethereum?","exampleUseCases":[{"title":"DeFi pre-swap approval check","prompt":"Before I swap, can you check how much of my USDC (0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48) the 1inch router at 0x1111111254EEB25477B68fb85Ed929f73A960582 is currently allowed to spend from my wallet 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045?"},{"title":"Token approval security audit","prompt":"I want to audit my wallet 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045 — can you check what allowance the Aave lending pool at 0x87870Bca3F3fD6335C3F4ce8392D69350B4fA4E2 has to spend my DAI tokens at 0x6B175474E89094C44Da98b954EedeAC495271d0F?"},{"title":"Smart contract allowance verification","prompt":"Check if the spender contract 0x68b3465833fb72A70ecDF485E0e4C7bD8665Fc45 still has a nonzero allowance to pull WETH (0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2) from address 0xAb5801a7D398351b8bE11C439e05C5B3259aeC9B on Ethereum mainnet."}],"resultDescription":"Returns a JSON object with an 'ok' boolean indicating success, a 'result' field containing the allowance as a uint256 decimal string, and metadata fields including 'chain', 'method', and 'service'. On failure, 'ok' is false and an 'error' string is present describing the issue.","failureModes":["Invalid address format (not 0x + 40 hex) returns a validation error","Contract address is not a valid ERC20 contract — call may revert or return unexpected data","Network/RPC connectivity issues causing timeout or error response","ok: false with error field when the on-chain call reverts","Missing required query parameters (token, owner, or spender) results in 400-level error"],"whenToPreferThis":"Use this endpoint when you need to read the current ERC20 allowance between a specific owner and spender on Ethereum mainnet without requiring a full node setup. Prefer this over general blockchain RPC calls when you want a clean, typed REST interface that returns the uint256 allowance as a human-readable decimal string with minimal setup. Ideal for pre-transaction validation, approval auditing, and DeFi automation workflows.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-02T00:44:50.303Z","isFirstParty":false,"canonicalSlug":"xerxes-erc20-allowance-lookup-804ad897"}