{"uid":"cap_QW32QWTpXcaLRAA8E10QH","slug":"base-mainnet-eth-balance-lookup-17bb65be","name":"Base Mainnet ETH Balance Lookup","description":"ETH balance of a Base mainnet address, incl. balance_usd.","url":"https://x402-data-api.sigrunner.workers.dev/chain/balance","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","properties":{"address":{"type":"string","description":"0x-prefixed 20-byte Base address"}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":{"type":"json","example":{"chain":"base","address":"0x4200000000000000000000000000000000000006","balance_eth":17.2654321,"balance_usd":31886.15,"balance_wei":"17265432100000000000"}},"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_Hoc92-11FVVO9PkNdo1HY","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 ETH balance (in ETH and USD) for a given Base mainnet wallet address.","exampleAgentPrompt":"What's the current ETH balance (and its USD value) for the Base mainnet wallet 0x4838B106FCe9647Bdf1E7877BF73cE8B0BAD5f97?","exampleUseCases":null,"resultDescription":"Returns the ETH balance of the specified Base mainnet address as a numeric value, along with its equivalent in USD (balance_usd), enabling quick assessment of a wallet's ETH holdings in both native and fiat terms.","failureModes":["Missing or malformed address query param — returns error or empty result","Address not found on Base mainnet (valid format but zero balance — returns 0)","Invalid 0x address format — returns validation error","Network/RPC timeout — returns 5xx or gateway error","Payment not processed (x402 micropayment failure) — returns 402"],"whenToPreferThis":"Use this endpoint when you specifically need the native ETH balance of a Base mainnet address expressed in both ETH and USD, and don't need token balances, transaction counts, or contract checks. For a fuller wallet overview, prefer the wallet bundle endpoint. For ERC-20 token balances, use the dedicated token balance endpoint.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-16T06:41:28.685Z","isFirstParty":false}