{"uid":"cap_l4fgiMyrtvCHSq1BrjkK4","slug":"plainchain-erc-20-allowance-lookup-8e78210b","name":"Plainchain ERC-20 Allowance Lookup","description":"Gas, balances, token data, address type, approvals, transaction decoding, x402 receipt verification and verifiable randomness on Base, Arbitrum, Ethereum and Optimism. No API key: pay $0.001-$0.01 per call in USDC on Base via x402.","url":"https://plainchain.appin60.com/v1/allowance?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","$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"],"type":"string"},"queryParams":{"type":"object","required":["owner","token","spender"],"properties":{"chain":{"type":"string","description":"base (default), arbitrum, ethereum or optimism; chain ids 8453, 42161, 1, 10 also work"},"owner":{"type":"string","pattern":"^0x[0-9a-fA-F]{40}$","description":"token holder"},"token":{"type":"string","pattern":"^0x[0-9a-fA-F]{40}$","description":"ERC-20 token"},"spender":{"type":"string","pattern":"^0x[0-9a-fA-F]{40}$","description":"approved spender, e.g. a router or Permit2"}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":{"type":"json","example":{"risk":"Spender can move the owner's entire balance of this token at any time. Revoke if you no longer use it.","chain":"Base","symbol":"USDC","allowance":"unlimited","unlimited":true}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.001042","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":"$0.001042/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001042","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001042","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_5wnLZQ4Hr4NbiN8O_nrqF","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.001042","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Returns the current ERC-20 token allowance (approved spending limit) granted by an owner to a spender on Base, Arbitrum, Ethereum, or Optimism, with a plain-language risk assessment.","exampleAgentPrompt":"Check how much USDC the Uniswap v3 router (0xE592427A0AEce92De3Edee1F18E0157C05861564) is approved to spend from my wallet (0xAbCd...1234) on Base — I want to know if it's unlimited and whether I should revoke it.","exampleUseCases":[{"title":"Audit risky unlimited DeFi approvals","prompt":"Check whether the Uniswap router at 0xE592427A0AEce92De3Edee1F18E0157C05861564 has unlimited approval to spend USDC (0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48) from my wallet 0xAbCd000000000000000000000000000000001234 on Ethereum — and tell me if I'm at risk."},{"title":"Verify Permit2 allowance before swap","prompt":"Before I do a swap, can you check the Permit2 contract allowance (0x000000000022D473030F116dDEE9F6B43aC78BA3) for my USDC on Base? My wallet is 0xBeef000000000000000000000000000000005678 and USDC is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913."},{"title":"Monitor token approval on Arbitrum","prompt":"What's the current spending allowance that the GMX router (0xaBBc5F99639c9B6bCb58544ddf04165ad8c4FfE9) has over my ARB tokens (0x912CE59144191C1204E64559FE8253a0e49E6548) from address 0xDead000000000000000000000000000000009999 on Arbitrum?"}],"resultDescription":"Returns a JSON object containing: the token symbol, the chain name, the allowance amount (either a numeric string or 'unlimited'), a boolean 'unlimited' flag, and a plain-English 'risk' string explaining what the approval means and whether the user should consider revoking it.","failureModes":["Invalid Ethereum address format for owner, token, or spender (must be 0x-prefixed 40 hex chars)","Unsupported chain identifier returns an error","Token address is not a valid ERC-20 contract (e.g. native ETH address)","Payment failure via x402 if USDC balance or approval on Base is insufficient","Network/RPC timeout for the queried chain"],"whenToPreferThis":"Use this endpoint when an AI agent needs to check ERC-20 token approval risk without setting up an API key — paying $0.001 per call in USDC via x402 on Base. Ideal for DeFi security audits, pre-swap approval checks, or wallet hygiene workflows across Base, Arbitrum, Ethereum, and Optimism. Prefer this over general blockchain RPC calls when you want a structured, human-readable risk assessment alongside the raw allowance value.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-14T12:37:10.763Z","isFirstParty":false,"canonicalSlug":"plainchain-erc-20-allowance-lookup-8e78210b"}