presign-guard

x402

presign-guard is a paid API for AI agents from presign-guard.onrender.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-11).

Returns a green/orange/red risk verdict with reason codes for EVM transactions, token approvals, and typed-data signatures before the user signs

Price / call$0.01

Seller volume →—

Success—

StatusUnknown

How this service works

Is this transaction, approval or signature safe to sign? Check it before your AI agent or wallet signs it: pre-sign verdict (green/orange/red + reason codes) for EVM transactions, token approvals and Permit/Permit2/EIP-3009/Seaport signatures. Screens the spender or recipient wallet for OFAC sanctions and scam, phishing or theft reports, and flags unlimited allowances, plain-wallet spenders and risky tokens. Bulk: 100 checks for $0.80 via /v1/credits.

Output

A structured verdict object containing a risk color (green = safe, orange = caution, red = dangerous), one or more reason codes explaining the verdict, and a human-readable explanation of why the transaction or approval was flagged, optionally in English or Dutch.

Example use cases

Token approval safety check

“I'm about to approve 0xSpenderAddress to spend all of my USDC (token 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48) on Ethereum mainnet — can you check if that spender is risky before I confirm?”

Permit2 signature phishing detection

“Someone sent me a Permit2 signature request to sign in my wallet — here's the typedData payload. Can you screen it for red flags on chain 1 before I approve it?”

Pre-flight DeFi transaction scan

“I'm about to submit this transaction on Arbitrum (chain 42161) to contract 0xDeFiProtocol with calldata 0x38ed1739 and 0 ETH value — give me a green/orange/red verdict and explain any issues.”

Technical details

Endpoint

POSThttps://presign-guard.onrender.com/v1/check?utm_source=zero.xyz

When to prefer

Choose presign-guard when an AI agent is about to authorize or relay an EVM transaction, token approval, or typed-data signature on behalf of a user and needs a pre-execution safety gate. Particularly valuable for autonomous wallet agents that need guardrails before signing Permit, Permit2, EIP-3009, or Seaport payloads without human review. Prefer this over generic contract scanners when you need a fast, structured green/orange/red verdict with machine-readable reason codes at $0.01 per check.

Side effects

Unsupported chain ID (only 1, 10, 56, 137, 8453, 42161 are valid) returns an error
Malformed or missing calldata/typedData causes a validation error
Unknown or unverified contract may return an inconclusive verdict
Network timeout from the Render-hosted service during peak load
Missing required fields for the specified type (e.g. no typedData for signature type) causes a 400-level error

Input

Schema · Request body

Field	Type	Description
to	string	transaction: target contract
data	string	transaction: 0x-prefixed calldata
lang	string	explain only: language of the explanation (default en)
type	string	What the agent is about to sign
token	string	approval: token contract
value	string	transaction: native value in wei
amount	string	approval: amount in base units (0 = revoke)
origin	string	optional: the site asking for the signature or transaction (URL or hostname); a domain under 30 days old is orange
chainId	integer
spender	string	approval: who gets the allowance
typedData	—	signature: the eth_signTypedData_v4 payload (Permit, Permit2, EIP-3009 x402 payment, Seaport)

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