Call before signing an Ethereum or Base transaction or calldata
Call before signing an Ethereum or Base transaction or calldata. Decodes raw transaction bytes or contract calldata against standard interfaces (ERC-20, ERC-721, ERC-1155, WETH, EIP-2612 Permit and Permit2) in memory. Returns the decoded method signature, typed parameters, value in wei and standard specification links. Mechanical byte decoding only: never simulates state or advises whether to sign.
Answeringour last check, 2026-09-28
1 of 1checks answered this week
29 msmedian answer time
$0.1listed price per call
$0.1price 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
POST https://preflight402.com/v1/evm/tx-inspect
| Category | Market data |
|---|---|
| Provider host | preflight402.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 |
|---|---|---|---|---|
| 2026-09-28 | valid payment request | 402 | $0.1 | 29 ms |
Example input (from the provider)
{
"body": {
"calldata": "0xa9059cbb000000000000000000000000222222222222222222222222222222222222222200000000000000000000000000000000000000000000000000000000000f4240",
"network": "base",
"to": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"
},
"bodyType": "json",
"method": "POST",
"type": "http"
}
Promised output schema (from the provider)
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"input": {
"additionalProperties": false,
"properties": {
"body": {
"additionalProperties": false,
"properties": {
"calldata": {
"pattern": "^0x([0-9a-fA-F]{2})*$",
"type": "string"
},
"network": {
"enum": [
"ethereum",
"base"
],
"type": "string"
},
"raw_tx": {
"pattern": "^0x([0-9a-fA-F]{2})*$",
"type": "string"
},
"to": {
"pattern": "^0x[0-9a-fA-F]{40}$",
"type": "string"
}
},
"required": [
"network"
],
"type": "object"
},
"bodyType": {
"enum": [
"json",
"form-data",
"text"
],
"type": "string"
},
"method": {
"enum": [
"POST"
],
"type": "string"
},
"type": {
"const": "http",
"type": "string"
}
},
"required": [
"type",
"method",
"bodyType",
"body"
],
"type": "object"
},
"output": {
"properties": {
"example": {
"type": "object"
},
"type": {
"type": "string"
}
},
"required": [
"type"
],
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
}