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SignCheck: EVM Transaction Safety Analyzer
x402
SignCheck: EVM Transaction Safety Analyzer is a paid API for AI agents from api.youraitools.co, paid per call via x402, $0.015/call, status unknown (last checked 2026-10-23).
Analyzes an EVM transaction (by contract address, calldata, value, and chain) and returns a safety verdict, risk score, flags, and decoded action summary to help users avoid malicious approvals and drainer contracts.
Price / call$0.015
Success—
StatusUnknown
How this service works
Transaction and signature safety check API for crypto wallets. Pre-sign safety check for agent wallets: send a transaction, EIP-712 typed data (Permit, Permit2, EIP-3009, Seaport), an EIP-7702 authorization, or an x402 402 + payment payload. Returns SAFE/CAUTION/DANGER, a plain-English summary and every risk flag (unlimited or EOA approvals, setApprovalForAll, fake USDC domains, x402 overpay, OFAC SDN) plus on-chain facts and eth_call simulation.
Output
Returns a JSON object with a top-level verdict (e.g. DANGER, WARN, SAFE), a numeric risk score (0–100), an array of flags each with a code, human-readable message and severity level (critical/medium/low), a decoded action label (e.g. erc20_approve), a summary sentence, a list of counterparty addresses with roles and labels, onchain simulation results including success status and block number, token metadata (name, symbol, decimals, address), OFAC sanctions screening results with match count, and chain information.
Example use cases
Catching unlimited token drainer approvals
“I'm about to approve a DeFi protocol on Base to spend my USDC — the calldata is 0x095ea7b3000000000000000000000000[address]ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff and it's going to 0x3c1A1E01e790Cd326495631B3b38Bd7068F08d6F. Can you run a safety check and tell me if this is a scam before I sign?”
OFAC sanctions screening for a counterparty
“I'm about to send ETH to 0xAbc123... on Ethereum mainnet — can you check if that address shows up on the OFAC SDN sanctions list and give me a risk verdict on the transaction?”
Decoding unknown calldata before signing
“My hardware wallet is asking me to sign something with hex calldata I don't recognize — it's on Base, to address 0xDef456..., value 0. Can you decode what this transaction actually does and flag anything suspicious?”
Technical details
Endpoint
GEThttps://api.youraitools.co/signcheck/v1/check?utm_source=zero.xyzWhen to prefer
Use this endpoint when an AI agent or user needs to validate a specific EVM transaction before signing — especially token approvals, contract interactions with unknown calldata, or transfers to unfamiliar addresses. It excels at catching drainer-kit patterns (unlimited approvals to EOAs), decoding calldata into human-readable summaries, running onchain simulations, and screening counterparties against OFAC sanctions. Prefer it over generic block explorers when you need a structured risk verdict with severity-ranked flags rather than raw on-chain data.
Side effects
- Missing required 'to' query parameter returns validation error
- Invalid or malformed calldata hex may result in undecoded action or partial analysis
- Unsupported chain identifier returns error or falls back to Base default
- Simulation may fail if 'from' address not provided or has insufficient balance
- Sanctions list may lag by days if 'list_date' is stale
- Non-EVM chains (Solana) are not supported and will error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"kind": "transaction",
"tier": "full",
"chain": {
"id": 8453,
"name": "Base"
},
"flags": [
{
"code": "SPENDER_IS_EOA",
"message": "The token allowance goes to 0x3c1A…8d6F, a plain wallet (no contract code). Legitimate apps approve contracts; approvals to wallets are how drainer kits steal funds.",
"severity": "critical"
},
{
"code": "UNLIMITED_APPROVAL",
"message": "Grants an UNLIMITED allowance to 0x3c1A…8d6F.",
"severity": "medium"
}
],
"action": "erc20_approve",
"engine": "signcheck-0.1",
"onchain": {
"block": 52942270,
"chain": "Base",
"tokens": [
{
"name": "USD Coin",
"symbol": "USDC",
"address": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"decimals": 6
}
],
"available": true,
"simulation": {
"success": true
}
},
"summary": "Approve 0x3c1A…8d6F to spend UNLIMITED USDC from your wallet",
"verdict": "DANGER",
"sanctions": {
"list": "US Treasury OFAC Specially Designated Nationals (SDN) list",
"matches": 0,
"list_date": "2026-10-21",
"evm_addresses": 124
},
"risk_score": 75,
"counterparties": [
{
"type": "eoa",
"label": null,
"roles": [
"spender"
],
"address": "0x3c1A1E01e790Cd326495631B3b38Bd7068F08d6F"
}
]
}
}Tags
x402
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