{"uid":"cap_6boynH_KdR-GoFqHzXPQ8","slug":"coin-railz-token-approval-transaction-generator-f183bdb2","name":"Coin Railz Token Approval Transaction Generator","description":"Token approval transaction generator - required infrastructure for DeFi agents (B2B2C infrastructure)","url":"https://coinrailz.com/x402/service/approval-manager","method":"POST","headers":{},"bodySchema":{"type":"object","required":["chain","amount","spender","tokenAddress"],"properties":{"chain":{"type":"string","description":"Blockchain network"},"amount":{"type":"string","description":"Amount to approve or 'unlimited'"},"spender":{"type":"string","description":"Spender address (DEX router)"},"tokenAddress":{"type":"string","description":"Token to approve"}}},"responseSchema":{"type":"object","properties":{"approvalTransaction":{"type":"object","description":"Approval transaction data"}}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.2","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":"$0.2/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.2","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.2","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_EiHmXqrAwgQ5ttrOrfete","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.2","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Generates ERC-20 token approval transactions for DeFi agents to authorize a spender (e.g. DEX router) to spend a specified amount of a given token on a blockchain network","exampleAgentPrompt":"Generate a token approval transaction on Ethereum to let the Uniswap v3 router (0xE592427A0AEce92De3Edee1F18E0157C05861564) spend up to 500 USDC (token address 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48) on my behalf.","exampleUseCases":null,"resultDescription":"Returns an approvalTransaction object containing the full transaction data (to, data, value, etc.) needed to submit an ERC-20 approve() call on-chain, authorizing the specified spender to transfer up to the given amount of the token.","failureModes":["Invalid or unrecognized chain identifier — returns error indicating unsupported network","Malformed token address or spender address — returns validation error","Amount value not parseable (must be numeric string or 'unlimited') — returns parsing error","Payment failure (insufficient USDC for $0.2 fee) — returns 402 Payment Required","Missing required fields (chain, amount, spender, tokenAddress) — returns 400 Bad Request"],"whenToPreferThis":"Use this endpoint when an AI agent needs to programmatically construct an ERC-20 token approval (allowance) transaction before executing a DeFi swap or interaction that requires a prior approve() call. Prefer this over manually encoding approve() calldata when you need a ready-to-broadcast transaction object for a specific chain and spender without managing ABI encoding yourself.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-13T18:41:29.825Z","isFirstParty":false}