{"uid":"cap_9KLa5rDzJqVpI72L2gM9x","slug":"base-chain-transaction-simulator-0dc73aed","name":"Base Chain Transaction 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/v1/chain-simulation?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_vQkN-dlJLAJCNflSOiS2q","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 and returns safety verdict, gas estimates, token transfers, and balance changes before sending on-chain","exampleAgentPrompt":"Before I send this USDC transfer on Base, simulate it for me — from 0xe4be4d0bd82d8e68203deff81f79ede0529f2617 to contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 with calldata 0x and 0.001 ETH value — tell me if it's safe, what the gas cost will be, and what token balances will change.","exampleUseCases":[{"title":"Pre-flight DeFi swap safety check","prompt":"Before I execute this DEX swap on Base, simulate the call from my wallet 0xe4be4d0bd82d8e68203deff81f79ede0529f2617 to the router at 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 — I need to know if it will succeed, how much gas it'll use, and what tokens move."},{"title":"Batch multicall simulation","prompt":"I want to run 3 contract calls in sequence on Base from address 0xe4be4d0bd82d8e68203deff81f79ede0529f2617 — simulate all of them together and tell me if the whole batch succeeds, what the total gas cost is, and whether any will revert."},{"title":"Smart contract interaction preview","prompt":"I'm about to call a contract on Base at 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 with some calldata — simulate it first from my address 0xe4be4d0bd82d8e68203deff81f79ede0529f2617 and give me the safety verdict, any token transfers that would happen, and the estimated fee in USD."}],"resultDescription":"Returns a JSON object with: overall success flag, safety verdict (e.g. SAFE_TO_SEND), per-call results including function signature decoded, gas used, and revert reason if any, total gas used and fee in ETH and USD, list of token transfers with sender/recipient/amount/symbol, balance changes by address and token, token approvals granted, current block number, and suggested next endpoints to call.","failureModes":["Invalid Ethereum address format returns 400 validation error","Malformed calldata hex string returns schema validation error","Simulated call reverts — returned with success:false and revert_reason populated","Payment not included or insufficient USDC returns 402 Payment Required","Network issues reaching Base RPC return 503 or timeout","More than 5 calls in batch array returns 400 error","Contract address not deployed on Base returns simulation failure"],"whenToPreferThis":"Use this endpoint when an AI agent needs to pre-validate any Base chain transaction before actual submission — especially for DeFi interactions, unfamiliar contracts, or multi-step sequences where a revert would be costly. Prefer this over on-chain execution when safety verification is needed, gas estimation is uncertain, or the agent must confirm token flows before committing. It requires no API key (x402 micropayment via USDC on Base) making it suitable for autonomous agent pipelines.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-31T18:40:39.912Z","isFirstParty":false,"canonicalSlug":"base-chain-transaction-simulator-0dc73aed"}