Simulate an EVM transaction before signing
Simulate an EVM transaction before signing. Decodes the calldata into a named function with arguments and security risk flags, AND runs a keyless static eth_call preview to tell you whether the transaction would succeed or revert (with the decoded revert reason). Use it to catch a failing or malicious transaction before you broadcast it. Read-only, no keys, no node infra. Asset-level change tracing is v2.
Answeringour last check, 2026-10-21
1 of 1checks answered this week
1270 msmedian answer time
$0.005listed price per call
$0.005price it asked us
Paid test badge: not yet. The checks above are free: we call the tool without paying and read the payment request it sends back. The Verified badge needs paid calls whose answers match the promised output, and nobody can buy a badge.
Endpoint
GET https://simulate.cyberwarex.com/simulate
| Category | Everything else |
|---|---|
| Provider host | simulate.cyberwarex.com |
| Networks | eip155:8453 |
| Payment schemes | exact |
| Self-reported calls, 30 days | 1 from 1 payers (the provider's figure, not ours) |
Our checks, last 30 days
| Day | Result | HTTP | Asked | Time |
|---|---|---|---|---|
| 2026-10-21 | valid payment request | 402 | $0.005 | 1270 ms |
Example input (from the provider)
{
"method": "GET",
"queryParams": {
"chain": "base",
"data": "0xa9059cbb000000000000000000000000d8da6bf26964af9d7eed9e03e53415d37aa960450000000000000000000000000000000000000000000000000000000005f5e100",
"from": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
"to": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"
},
"type": "http"
}
Promised output schema (from the provider)
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"input": {
"additionalProperties": false,
"properties": {
"method": {
"enum": [
"GET",
"HEAD",
"DELETE"
],
"type": "string"
},
"queryParams": {
"additionalProperties": false,
"properties": {
"chain": {
"default": "base",
"description": "EVM chain to simulate on.",
"enum": [
"base",
"ethereum",
"arbitrum",
"optimism",
"polygon",
"bsc"
],
"type": "string"
},
"data": {
"description": "Transaction calldata (hex).",
"pattern": "^0x[a-fA-F0-9]*$",
"type": "string"
},
"from": {
"description": "Sender address for the eth_call preview.",
"pattern": "^0x[a-fA-F0-9]{40}$",
"type": "string"
},
"to": {
"description": "Target contract or account address.",
"pattern": "^0x[a-fA-F0-9]{40}$",
"type": "string"
},
"value": {
"description": "Native value in wei (optional, decimal or 0x hex).",
"type": "string"
}
},
"required": [
"to"
],
"type": "object"
},
"type": {
"const": "http",
"type": "string"
}
},
"required": [
"type",
"method"
],
"type": "object"
},
"output": {
"properties": {
"example": {
"properties": {
"asset_changes": {
"description": "v2: needs a tracing RPC key.",
"type": "null"
},
"chain": {
"type": "string"
},
"decoded": {
"description": "function, signature, args.",
"type": "object"
},
"disclaimer": {
"type": "string"
},
"note": {
"type": "string"
},
"revert_reason": {
"type": [
"string",
"null"
]
},
"risk": {
"description": "level (none|caution|danger) + flags.",
"type": "object"
},
"to": {
"type": "string"
},
"would_succeed": {
"type": [
"boolean",
"null"
]
}
},
"type": "object"
},
"type": {
"type": "string"
}
},
"required": [
"type"
],
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
}