{"uid":"cap_5SWEevwBPJahCmfA0ISqr","slug":"base-transaction-gas-estimator-simulator-c0fd1ad8","name":"Base Transaction Gas Estimator & Simulator","description":"Pay-per-call crypto microdata for trading/onchain AI agents via x402 (USDC on Base): Base gas, token risk, balances, multi-venue prices, Hyperliquid book/funding, kimchi premium. No API keys.","url":"https://kr-x402-mvp.kgy5612.workers.dev/api/chain/estimate-gas?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET"],"type":"string"},"queryParams":{"type":"object","properties":{"to":{"type":"string","pattern":"^0x[0-9a-fA-F]{40}$","examples":["0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"],"description":"Target contract or recipient"},"data":{"type":"string","pattern":"^0x([0-9a-fA-F]{2})*$","description":"Calldata (default 0x)"},"from":{"type":"string","pattern":"^0x[0-9a-fA-F]{40}$","examples":["0xe4be4d0bd82d8e68203deff81f79ede0529f2617"],"description":"Sender (signer) address"},"calls":{"type":"string","description":"URL-encoded JSON array of up to 5 {to,data,value_eth|value} run in order from the same sender"},"value_eth":{"type":"string","examples":["0.01"],"description":"ETH to send, decimal (default 0)"}},"additionalProperties":false}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":{"type":"json","example":{"from":"0xe4be4d0bd82d8e68203deff81f79ede0529f2617","next":["/crypto/base-gas","/crypto/tx-status?hash="],"block":53272234,"calls":[{"to":"0x833589fcd6edb6e08f4c7c32d4f71b54bda02913","index":0,"success":true,"function":"transfer(address,uint256)","gas_used":45047,"revert_reason":null}],"chain":"base","flags":[],"fee_eth":5e-7,"fee_usd":0.0019,"success":true,"summary":"1 call succeeds; sender sends 0.001 USDC","verdict":"SAFE_TO_SEND","approvals":[],"transfers":[{"to":"0xa587d73489f8f09d1975f1ddbb1c61c93e8fa9d7","from":"0xe4be4d0bd82d8e68203deff81f79ede0529f2617","token":"0x833589fcd6edb6e08f4c7c32d4f71b54bda02913","amount":0.001,"symbol":"USDC"}],"gas_used_total":45047,"sender_changes":{"USDC":-0.001},"balance_changes":{"0xa587d73489f8f09d1975f1ddbb1c61c93e8fa9d7":{"USDC":0.001},"0xe4be4d0bd82d8e68203deff81f79ede0529f2617":{"USDC":-0.001}}}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.003","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":"$0.003/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.003","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.003","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_VM1CKhP41ZQ5XN2jVGBTi","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.003","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Simulates one or more Base chain transactions, estimating gas cost, USD fee, token transfers, approval changes, and safety verdict before sending.","exampleAgentPrompt":"Before I send this USDC transfer on Base — from 0xe4be4d0bd82d8e68203deff81f79ede0529f2617 to contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 with calldata 0xa9059cbb — can you simulate it and tell me the gas cost in USD, whether it will succeed, and what token balances will change?","exampleUseCases":[{"title":"Pre-flight check before DeFi swap","prompt":"I'm about to call a Uniswap router on Base with this calldata — can you simulate the transaction from my address 0xe4be4d0bd82d8e68203deff81f79ede0529f2617 and tell me if it'll succeed, how much gas it will cost in USD, and what tokens will move?"},{"title":"Batch simulate agent payment sequence","prompt":"I need to dry-run three sequential contract calls on Base from sender 0xe4be4d0bd82d8e68203deff81f79ede0529f2617 — simulate them in order and tell me total gas used, whether each succeeds, and any USDC balance changes across all three."},{"title":"Revert risk check before NFT mint","prompt":"Check whether this mint calldata to contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 from my wallet 0xe4be4d0bd82d8e68203deff81f79ede0529f2617 sending 0.01 ETH will revert on Base, and give me the verdict plus estimated fee."}],"resultDescription":"Returns a JSON object with: overall success/revert verdict (SAFE_TO_SEND or revert reason), total gas used, fee in ETH and USD, per-call breakdown (function signature, gas used, success, revert reason), detected token transfers with amounts and symbols, approval changes, net balance changes per address, current block number, and suggested next API endpoints.","failureModes":["Invalid address format returns 400 validation error","Calldata that causes revert returns success:false with revert_reason populated","Malformed calls JSON array returns parse error","Missing required 'to' for single-call mode may return incomplete simulation","Network congestion on Base RPC may cause timeout","Payment failure via x402 (insufficient USDC) blocks the call entirely"],"whenToPreferThis":"Use this endpoint when an AI agent needs to pre-flight a Base chain transaction before broadcasting — especially to check for reverts, estimate USD gas cost, or audit token flows without spending gas. Prefer over raw RPC eth_estimateGas calls because this endpoint also decodes function names, enumerates token transfers and approvals, gives a USD fee estimate, and provides a human-readable safety verdict. Supports batching up to 5 sequential calls. Requires no API key — pay $0.003 USDC per call via x402.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-31T18:41:49.146Z","isFirstParty":false,"canonicalSlug":"base-transaction-gas-estimator-simulator-c0fd1ad8"}