{"uid":"cap_7LVFmQf0OYgkNvdC0Aym_","slug":"x402-chain-tools-native-eth-balance-lookup-6c2ce53e","name":"x402 Chain Tools – Native ETH Balance Lookup","description":"Get the native ETH balance of a Base address.","url":"https://blockchain-api.x402-chain-tools.workers.dev/chain/balance","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"address":{"type":"string","pattern":"^0x[0-9a-fA-F]{40}$","description":"Base wallet address."}}},"responseSchema":{"type":"json","example":{"ok":true,"address":"0x0000000000000000000000000000000000000001","balance":{"eth":"0","wei":"0"},"network":"eip155:8453"}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.001","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":"$0.001/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_m-LSdP8kNSazxpSL181K7","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.001","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Returns the native ETH balance (in both ETH and wei) of a given Base Mainnet wallet address.","exampleAgentPrompt":"What's the current ETH balance for Base wallet address 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045? Give me both the ETH and wei amounts.","exampleUseCases":[{"title":"Portfolio ETH balance snapshot","prompt":"Check how much ETH is sitting in my Base wallet 0xAb5801a7D398351b8bE11C439e05C5B3259aeC9B right now — show me the balance in both ETH and wei."},{"title":"Pre-transaction ETH sufficiency check","prompt":"Before I send a transaction on Base, can you check whether wallet 0x71C7656EC7ab88b098defB751B7401B5f6d8976F has any native ETH to cover gas fees?"},{"title":"Automated wallet monitoring alert","prompt":"I want to keep an eye on this Base address 0x3fC91A3afd70395Cd496C647d5a6CC9D4B2b7FAD — what's its current ETH balance so I can set a low-balance threshold alert?"}],"resultDescription":"A JSON object containing ok (boolean success flag), the queried address, a balance object with 'eth' (human-readable ETH string) and 'wei' (raw integer string), and the network identifier 'eip155:8453' confirming Base Mainnet.","failureModes":["Invalid address format (not a 0x + 40 hex char string) returns validation error","Address not found on Base Mainnet (returns balance of 0, not an error)","RPC node timeout or Base network congestion causes delayed or failed response","Malformed request body returns 400-level error","Payment failure (x402) prevents the call from being processed"],"whenToPreferThis":"Use this endpoint when you specifically need the native ETH balance (not ERC-20 tokens) of a Base Mainnet address. Prefer this over generic blockchain explorers when you need a structured JSON response suitable for programmatic use in an agent workflow. Choose the sibling ERC-20 balance endpoint if you need token balances instead.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-14T06:39:56.993Z","isFirstParty":false}