{"uid":"cap_PnH_nq1u2QKZoIlWuBDBK","slug":"base-chain-transaction-simulator-54363762","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/crypto/simulate?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_ckHHfmY2kHxbY-D7ZdLMF","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 Ethereum/Base transactions to predict outcomes, gas costs, token transfers, and safety verdicts before sending on-chain","exampleAgentPrompt":"Before I send this USDC transfer on Base, simulate the transaction from 0xe4be4d0bd82d8e68203deff81f79ede0529f2617 to contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 with calldata 0xa9059cbb... and tell me if it'll succeed, how much gas it'll use, and what token balance changes to expect.","exampleUseCases":[{"title":"Pre-flight check before DeFi swap","prompt":"I'm about to call a DEX router on Base to swap ETH for USDC — can you simulate the transaction from my wallet 0xe4be4d0bd82d8e68203deff81f79ede0529f2617 to 0x2626664c2603336E57B271c5C0b26F421741e481 with value 0.05 ETH and the swap calldata, and tell me if it'll succeed, what I'll receive, and what the gas fee will be?"},{"title":"Safe-send check for a token transfer","prompt":"Before I send 50 USDC to 0xa587d73489f8f09d1975f1ddbb1c61c93e8fa9d7 on Base using the USDC contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913, simulate it and give me a SAFE_TO_SEND or REVERT verdict along with the expected balance changes."},{"title":"Batch transaction dry-run for an agent workflow","prompt":"I have 3 sequential contract calls I want to run from 0xe4be4d0bd82d8e68203deff81f79ede0529f2617 on Base — an approve, a deposit, and a stake. Can you simulate all three in order and tell me which ones succeed, total gas used, and any reverts before I actually send them?"}],"resultDescription":"Returns a JSON object with: overall success flag, a human-readable summary and SAFE_TO_SEND/REVERT verdict, per-call results (function decoded, gas used, revert reason if any), total gas used, fee in ETH and USD, list of token transfers with amounts and symbols, net balance changes per address, approval events, and suggested next endpoints to call.","failureModes":["Invalid address format returns schema validation error","Malformed calldata (non-hex) rejected with 400","Simulation of calls requiring large ETH value may fail if sender has no balance on Base fork","Rate limiting or payment failure via x402 returns 402 Payment Required","Batch exceeding 5 calls rejected","Network congestion may cause stale block data in simulation results"],"whenToPreferThis":"Use this endpoint when an AI agent needs to safely pre-check any Base chain transaction — especially before sending DeFi interactions, token transfers, or multi-step contract calls — to get a decoded, human-readable verdict with balance changes and gas estimates without risking actual funds. Prefer this over raw eth_call when you need decoded function names, token transfer summaries, and safety verdicts in one structured response. No API key is required; payment is micro-billed per call via x402/USDC.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-31T18:42:18.260Z","isFirstParty":false,"canonicalSlug":"base-chain-transaction-simulator-0dc73aed"}