{"uid":"cap__2_oKe5HK6yY-lg8MniSg","slug":"gas-oracle-multi-chain-fee-estimator-e281421f","name":"Gas Oracle — Multi-Chain Fee Estimator","description":"Interactive Bitcoin 4-year halving cycle chart on a polar disc. Live price, 200W MA, Mayer Multiple, RSI, MACD, Pi Cycle and optional paid cycle projections.","url":"https://4yearcycle.com/x402/gas-oracle","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET"],"type":"string"},"queryParams":{"type":"object","required":[],"properties":{"chains":{"type":"string","default":"base,ethereum,bitcoin","pattern":"^[a-z]+(,[a-z]+)*$","examples":["base,ethereum,bitcoin","base","eth,btc"],"description":"Comma-separated chains to quote: base, ethereum (alias eth), bitcoin (alias btc). Default: base,ethereum,bitcoin."}},"additionalProperties":false}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object","required":["count","chains"],"properties":{"count":{"type":"integer","description":"Number of chain quotes returned"},"chains":{"type":"array","items":{"type":"object","required":["chain","kind","fetchedAt"],"properties":{"rpc":{"type":"string","description":"EVM only: which public RPC answered"},"kind":{"enum":["evm","btc"],"type":"string","description":"Fee model: evm = gwei fields, btc = satPerVb field"},"chain":{"type":"string","description":"Canonical chain name: base, ethereum or bitcoin"},"satPerVb":{"type":"object","properties":{"fast":{"type":"number"},"slow":{"type":"number"},"normal":{"type":"number"},"minimum":{"type":"number"}},"description":"Bitcoin only: fee-rate tiers in sat/vB from mempool.space (slow ≈ 1h, normal ≈ 30min, fast = next block)"},"fetchedAt":{"type":"integer","description":"Epoch ms when this chain was actually fetched (server caches for 60 s)"},"baseFeeGwei":{"type":"number","description":"EVM only: pending-block EIP-1559 base fee in gwei"},"gasPriceGwei":{"type":"number","description":"EVM only: legacy eth_gasPrice suggestion in gwei"},"priorityGwei":{"type":"object","properties":{"fast":{"type":["number","null"]},"slow":{"type":["number","null"]},"normal":{"type":["number","null"]}},"description":"EVM only: suggested priority fee (tip) tiers in gwei; add to baseFeeGwei for an effective per-gas price"}}},"description":"One quote per requested chain, in requested order"}}}}}}},"responseSchema":{"type":"json","example":{"count":3,"chains":[{"rpc":"https://mainnet.base.org","kind":"evm","chain":"base","fetchedAt":1787054938980,"baseFeeGwei":0.005,"gasPriceGwei":0.006,"priorityGwei":{"fast":0.0085,"slow":0,"normal":0.001}},{"rpc":"https://ethereum-rpc.publicnode.com","kind":"evm","chain":"ethereum","fetchedAt":1787054938937,"baseFeeGwei":0.06,"gasPriceGwei":0.0572,"priorityGwei":{"fast":1,"slow":0.0001,"normal":0.0054}},{"kind":"btc","chain":"bitcoin","satPerVb":{"fast":2,"slow":1,"normal":1,"minimum":1},"fetchedAt":1787054938881}]}},"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_0ST_Iwcb3MxueOlllGj3U","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 current gas fee estimates for Base, Ethereum, and/or Bitcoin networks in a single call.","exampleAgentPrompt":"What are the current gas fees on Ethereum and Base, and what's the fast sat/vB rate for Bitcoin right now?","exampleUseCases":[{"title":"Pre-send fee check for crypto wallet","prompt":"Before I send this Ethereum transaction, can you check the current base fee and fast priority fee on Ethereum mainnet so I know what to set?"},{"title":"Bitcoin mempool cost monitoring","prompt":"What are the current Bitcoin fee tiers — slow, normal, and fast sat per vbyte — from mempool right now?"},{"title":"Multi-chain fee dashboard refresh","prompt":"Pull the latest gas estimates for Base, Ethereum, and Bitcoin all at once so I can update my dashboard."}],"resultDescription":"A JSON object containing a count of chains queried and an array of per-chain fee objects. EVM chains (Base, Ethereum) include baseFeeGwei, gasPriceGwei, priorityGwei tiers (fast/normal/slow), and the RPC endpoint used. Bitcoin includes satPerVb tiers (fast/normal/slow/minimum). All entries include the chain name, kind (evm or btc), and fetchedAt epoch timestamp. Data is cached server-side for 60 seconds.","failureModes":["Invalid chain name in query param returns an error or empty results","Upstream RPC or mempool.space outage may cause stale or missing chain data","Malformed chains query param (wrong delimiter or unsupported alias) may be rejected","Payment of 0.005 USDC not provided or x402 handshake fails — returns 402 Payment Required","Network timeout from upstream RPC results in missing chain entry"],"whenToPreferThis":"Choose this endpoint when you need real-time gas fee data across Base, Ethereum, and/or Bitcoin in a single lightweight call. It is ideal for wallets, trading bots, or automation agents that need to select an appropriate fee tier before broadcasting a transaction. Prefer it over chain-specific RPC calls when you need multi-chain coverage simultaneously, or when you need Bitcoin sat/vB estimates alongside EVM gwei data in one response.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-13T18:44:48.300Z","isFirstParty":false}