# ScanPay Transaction Preflight Simulator

> ScanPay Transaction Preflight Simulator is a paid API for AI agents from scanpay-ob3w.onrender.com, paid per call via x402, $0.05/call, status unknown (last checked 2026-10-31).

Simulates and security-scans a blockchain transaction before broadcast, returning a risk verdict and findings for Base, Ethereum, or Solana chains

## Facts

- Endpoint: POST https://scanpay-ob3w.onrender.com/v2/preflight/simulate?utm_source=zero.xyz
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-31
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/scanpay-transaction-preflight-simulator-ec25bc86
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_-SK_eqTibdYT4MWnkMZfD

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability scanpay-transaction-preflight-simulator-ec25bc86 -d '<json body>'
```

Example prompt: Before I broadcast this transaction on Base — it calls contract 0xabc with this data payload — run it through ScanPay's preflight simulator and tell me the risk score and whether it's safe to send.

## When to prefer this

Use this endpoint when an AI agent or wallet needs a deterministic, pre-broadcast safety gate for blockchain transactions on Base, Ethereum, or Solana. It is especially valuable when automating transactions where a human is not reviewing the calldata in real time, or when interacting with unfamiliar smart contracts. Prefer this over generic RPC simulation when you need an explicit security verdict and risk score, not just execution trace output.

## Known failure modes

- Missing required 'tx' or 'chain' field returns a validation error
- Unsupported chain value returns an error (only 'base', 'ethereum', 'solana' accepted)
- Malformed transaction object may result in simulation failure or partial analysis
- Payment not included or insufficient USDC triggers 402 payment required response
- Service unavailable on Render cold-start may cause timeout or 502 error

## How this service works

Deterministic AST code security scanner with x402 Solana micropayments, remote MCP, and ERC-8183 Evaluator oracle.

## Output

A JSON object containing a list of security findings (empty if none), an execution_gate object with a verdict string (ALLOW or DENY), a numeric risk_score, and a boolean allow_broadcast indicating whether the transaction is safe to broadcast.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "tx",
  "chain"
 ],
 "properties": {
  "tx": {
   "type": "object",
   "description": "Transaction object ({to, data, value} or {instructions})"
  },
  "chain": {
   "type": "string",
   "description": "Target chain: 'base', 'ethereum', or 'solana'"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "findings": [],
  "execution_gate": {
   "verdict": "ALLOW",
   "risk_score": 0,
   "allow_broadcast": true
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/scanpay-transaction-preflight-simulator-ec25bc86/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from scanpay-ob3w.onrender.com](https://www.zero.xyz/host/scanpay-ob3w.onrender.com/llms.txt)