{"uid":"cap_EAr9Mboj7fAjzjJHWQcv3","slug":"base-mainnet-chain-head-block-height-base-fee-1e2c599b","name":"Base Mainnet Chain Head (Block Height & Base Fee)","description":"Current Base mainnet block height and base fee per gas in wei, read from the chain at request time","url":"https://canary.countersignpay.com/v1/base/head?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","properties":{}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object","required":["blockHeight","baseFeePerGas","network","observedAt"],"properties":{"network":{"type":"string","description":"CAIP-2 chain id, always eip155:8453"},"observedAt":{"type":"string","description":"ISO 8601 time the chain was read"},"blockHeight":{"type":"string","description":"Latest block number on Base mainnet, decimal string"},"baseFeePerGas":{"type":"string","description":"Base fee per gas of that block, in wei, decimal string"}}}}}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.01","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":"$0.01/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_taBJUXAhIeKmK1_-tVgfj","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.01","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Returns the current block height and base fee per gas in wei for the Base mainnet, read live from the chain at request time.","exampleAgentPrompt":"What's the current block height and base fee per gas on Base mainnet right now?","exampleUseCases":[{"title":"Gas fee estimation before transaction","prompt":"Before I submit this transaction on Base, can you check the current base fee per gas so I know what to expect to pay?"},{"title":"Real-time Base chain monitoring","prompt":"What block is Base mainnet currently on, and what's the base fee right now? I want to track whether the network is congested."},{"title":"DApp synchronization check","prompt":"Pull the latest block height and base fee from Base mainnet so I can verify my app is in sync with the chain."}],"resultDescription":"Returns a JSON object with four fields: blockHeight (latest block number on Base mainnet as a decimal string), baseFeePerGas (base fee of that block in wei as a decimal string), network (CAIP-2 chain ID, always 'eip155:8453'), and observedAt (ISO 8601 timestamp of when the chain was read).","failureModes":["RPC node temporarily unavailable — endpoint may return 5xx or timeout","Network congestion may cause slight staleness in observedAt timestamp","Payment failure via x402 protocol returns 402 with payment details","Invalid method (non-GET) returns error"],"whenToPreferThis":"Use this endpoint when you need a live, point-in-time snapshot of Base mainnet chain head data — specifically block height and base fee per gas — without running your own node or RPC connection. Ideal for gas estimation, chain synchronization checks, or any agent workflow that needs current on-chain conditions on Base (eip155:8453) specifically, as opposed to Ethereum mainnet or other L2s.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-29T06:32:01.322Z","isFirstParty":false,"canonicalSlug":"base-mainnet-chain-head-block-height-base-fee-1e2c599b"}