{"uid":"cap_8Y2ZHerYx6Ja5iuxhT-lJ","slug":"erc-20-token-allowance-lookup-optimism-99d2be44","name":"ERC-20 Token Allowance Lookup (Optimism)","description":"ERC-20 Allowance (optimism). Optimism ERC-20 allowance: how much a spender may move from an owner, human-readable, with an unlimited-approval flag.","url":"https://saylorinnovations.com/api/evm/optimism/allowance/:address/:address2/:address3?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":null,"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.002","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"registry","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_tcR0fDuJsx2Y9IfsocZsz","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.002","costPer":"request","priority":0,"asset":null,"unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Returns the ERC-20 token allowance granted by a token holder to a spender on the Optimism network","exampleAgentPrompt":"Check the ERC-20 allowance on Optimism for token contract 0x4200000000000000000000000000000000000042, where the owner is 0xAbCd...1234 and the spender is 0xDeFi...5678 — I want to know how many tokens that spender is approved to use.","exampleUseCases":[{"title":"Verify DeFi protocol spending approval","prompt":"On Optimism, how many USDC tokens has my wallet 0xAbc...123 approved the Uniswap router 0xDef...456 to spend? The USDC contract is 0x7F5c764cBc14f9669B88837ca1490cCa17c31607."},{"title":"Audit token allowances before revoking","prompt":"I want to audit my token approvals — can you check the allowance for token contract 0x4200...0042 on Optimism where my wallet 0xOwner...789 is the holder and the suspected stale contract 0xOld...999 is the spender?"},{"title":"Monitor smart contract approval limits","prompt":"Before triggering a swap, check whether the spender contract 0xRouter...321 has enough allowance to move tokens from 0xUser...654 on Optimism — the token is at contract address 0xToken...111."}],"resultDescription":"Returns the numeric allowance amount (in the token's base units) that a spender address is permitted to transfer on behalf of the owner address for the specified ERC-20 token contract on the Optimism network. Typically includes the raw allowance value as a big integer.","failureModes":["Invalid or malformed Ethereum address returns an error or zero allowance","Contract address is not a valid ERC-20 token contract — call may fail or return unexpected data","Network connectivity issues to Optimism RPC nodes may cause timeouts","Allowance is zero if the owner has never approved the spender — not an error, but a valid zero result","Rate limiting or payment failure may block the request"],"whenToPreferThis":"Use this endpoint when you specifically need to query ERC-20 token allowances on the Optimism L2 network. Prefer this over generic RPC calls when you need a simple, pay-per-call REST API without managing your own Optimism node or RPC credentials. Ideal for agents that need to verify DeFi approval states, audit token permissions, or gate actions on whether a contract has sufficient spending approval on Optimism.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-03T00:48:46.906Z","isFirstParty":false,"canonicalSlug":"erc-20-token-allowance-lookup-optimism-99d2be44"}