Transaction Simulation API

The simulation API lets you preview transaction execution against the current chain state. It returns gas estimates, state changes, event logs, and a risk score that flags potentially dangerous transactions.

Endpoint

`POST /simulateTransaction`

Also available via WebSocket gateway as mev_simulateTx.

Request:

{
  "chain_id": 1,
  "from": "0x1234...abcd",
  "to": "0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D",
  "data": "0x38ed1739000000000000000000000000...",
  "value": "0x0",
  "gas_limit": 300000,
  "block_number": "latest"
}

Response:

{
  "success": true,
  "gas_used": 182340,
  "effective_gas_price": "25000000000",
  "output": "0x00000000000000000000000000000000000000000000003635c9adc5dea00000",
  "logs": [
    {
      "address": "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2",
      "topics": ["0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"],
      "data": "0x..."
    }
  ],
  "state_changes": [
    {
      "address": "0xC02aaA39...",
      "key": "0x03",
      "before": "0x1000",
      "after": "0x0f00"
    }
  ],
  "risk_score": 0.15,
  "risk_factors": [],
  "revert_reason": null
}

Risk Scoring

The simulation engine assigns a risk score between 0 and 1 based on detected patterns:

Score Range	Level	Description
0.0 -- 0.3	Low	Standard transaction. No suspicious patterns detected.
0.3 -- 0.7	Medium	Potential risks identified (e.g., high slippage, unknown contract).
0.7 -- 1.0	High	Dangerous patterns detected (e.g., approval to known phishing address, honeypot token, rug pull signatures).

Risk factors are returned as an array of strings describing each detected issue:

{
  "risk_score": 0.82,
  "risk_factors": [
    "approval_to_unverified_contract",
    "token_has_transfer_fee",
    "contract_deployed_recently"
  ]
}

Pricing Tiers

Tier	Rate Limit	Price	Features
Free	10 req/min	$0	Basic simulation, risk score.
Builder	500 req/min	$49/mo	State overrides, full traces.
Searcher	5,000 req/min	$199/mo	Priority execution, batch simulation.
Enterprise	Unlimited	Custom	Dedicated infra, SLA, custom chains.

SDK Usage

TypeScript

import { MEVGatewayClient } from "@yoorquezt/sdk-mev";

const client = new MEVGatewayClient("ws://localhost:9099/ws", {
  apiKey: process.env.YQ_API_KEY,
});

const result = await client.call("mev_simulateTx", {
  chainId: 1,
  from: "0x1234...abcd",
  to: "0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D",
  data: "0x38ed1739...",
  value: "0x0",
});

if (result.success && result.riskScore < 0.3) {
  console.log("Safe to submit. Gas estimate:", result.gasUsed);
} else {
  console.warn("Risk detected:", result.riskFactors);
}

Code Examples

Simulate a transaction

curl -X POST https://mev.yoorquezt.io/simulateTransaction \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $API_KEY" \
  -d '{
    "chain_id": 1,
    "from": "0x1234...abcd",
    "to": "0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D",
    "data": "0x38ed1739...",
    "value": "0x0",
    "gas_limit": 300000
  }'

Check risk score

curl -s -X POST https://rpc.yoorquezt.com/v1/simulate \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $API_KEY" \
  -d '{"chain_id":1,"from":"0x...","to":"0x...","data":"0x...","value":"0x0"}' \
  | jq '{success: .success, risk: .risk_score, factors: .risk_factors}'