{"uid":"cap_bT7783idL-Q0mQ773_FWP","slug":"base-onchain-balance-checker-60523845","name":"Base Onchain Balance Checker","description":"Native ETH balance of a Base wallet plus the balances of up to 20 ERC-20 tokens you list, formatted with each token's symbol and decimals, read live from Base.","url":"https://onchaincheck.dev/base/balances?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET"],"type":"string"},"queryParams":{"type":"object","required":["address"],"properties":{"tokens":{"type":"string","pattern":"^(0x[0-9a-fA-F]{40})(,0x[0-9a-fA-F]{40}){0,19}$","description":"Comma-separated ERC-20 contract addresses on Base, up to 20"},"address":{"type":"string","pattern":"^0x[0-9a-fA-F]{40}$","description":"Wallet address on Base"}},"additionalProperties":false}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":{"type":"json","example":{"chain":"base","tokens":[{"raw":"3528717773","token":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","symbol":"USDC","balance":"3528.717773","decimals":6},{"raw":"886309838294787826109722","token":"0x4ed4E862860beD51a9570b96d89aF5E1B0Efefed","symbol":"DEGEN","balance":"886309.838294787826109722","decimals":18}],"address":"0x2211d1D0020DAEA8039E46Cf1367962070d77DA9","nativeSymbol":"ETH","nativeBalance":"7.554675633166555733"}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.005","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":"$0.005/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.005","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.005","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_oK-i8IwwW-USx6SaMrQ96","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.005","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 and up to 20 ERC-20 token balances for a given Base wallet address, formatted with symbols and decimals.","exampleAgentPrompt":"What's the current ETH balance and USDC and DEGEN token balances for the Base wallet 0x2211d1D0020DAEA8039E46Cf1367962070d77DA9? The USDC contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 and DEGEN is 0x4ed4E862860beD51a9570b96d89aF5E1B0Efefed.","exampleUseCases":[{"title":"DeFi portfolio snapshot for a user","prompt":"Pull the current ETH balance plus USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) and cbETH (0x2Ae3F1Ec7F1F5012CFEab0185bfc7aa3cf0DEc22) balances for my Base wallet 0x2211d1D0020DAEA8039E46Cf1367962070d77DA9 — show me each with the proper decimals."},{"title":"Pre-transaction balance verification","prompt":"Before I send a transaction, check whether the Base wallet 0xAb5801a7D398351b8bE11C439e05C5B3259aeC9B has at least 500 USDC — the USDC contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913."},{"title":"Whale wallet monitoring alert","prompt":"Check the live token balances on Base for wallet 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045, including DEGEN (0x4ed4E862860beD51a9570b96d89aF5E1B0Efefed) and Brett (0x532f27101965dd16442E59d40670FaF5eBB142E4), so I can see if they've moved any significant holdings."}],"resultDescription":"A JSON object containing the wallet address, the native ETH balance as a decimal string, and an array of token objects each with the contract address, symbol, decimals, raw integer balance, and human-readable decimal balance. All values are read live from Base at call time.","failureModes":["Invalid wallet address format (non-0x or wrong length) causes a 400 error","Invalid ERC-20 contract address in the tokens list returns an error or omits that token","Token contract address is not a valid ERC-20 on Base — may return zero or an error","More than 20 token addresses provided — rejected by schema validation","Base network RPC outage causes timeout or 503 response","Rate limiting or payment failure returns a 402 or 429 response"],"whenToPreferThis":"Choose this endpoint when you need live, human-readable token balances from the Base network specifically, covering both native ETH and multiple ERC-20s in a single call. It is ideal when you need properly formatted decimals and token symbols without doing your own on-chain RPC calls. Prefer it over generic block explorer APIs when you need structured JSON output for up to 20 tokens simultaneously and are already working within the Base ecosystem.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-29T12:50:19.995Z","isFirstParty":false,"canonicalSlug":"base-onchain-balance-checker-60523845"}