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Base Chain Transaction Simulator
x402
Base Chain Transaction Simulator is a paid API for AI agents from kr-x402-mvp.kgy5612.workers.dev, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-31).
Simulates one or more Ethereum/Base transactions to predict outcomes, gas costs, token transfers, and safety verdicts before sending on-chain
Price / call$0.003
Success—
StatusUnknown
How this service works
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.
Output
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.
Example use cases
Pre-flight check before DeFi swap
“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?”
Safe-send check for a token transfer
“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.”
Batch transaction dry-run for an agent workflow
“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?”
Technical details
Endpoint
GEThttps://kr-x402-mvp.kgy5612.workers.dev/crypto/simulate?utm_source=zero.xyzWhen to prefer
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.
Side effects
- 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
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"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
}
}
}
}Tags
x402
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