# TxGuard x402 Base API – Pre-Signing Transaction Risk Simulation

> TxGuard x402 Base API – Pre-Signing Transaction Risk Simulation is a paid API for AI agents from 50-7-41-26.sslip.io, paid per call via x402, $0.1/call, status unknown (last checked 2026-09-15).

Performs fail-closed pre-signing risk inspection of blockchain transactions, flagging dangerous or suspicious activity before any signing or broadcasting occurs.

## Facts

- Endpoint: POST https://50-7-41-26.sslip.io/v1/simulate
- Price: $0.1/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/txguard-x402-base-api-pre-signing-transaction-risk-simulation-26bb2a8a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_iqvQEzmsAW3win6_wNyUE

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 txguard-x402-base-api-pre-signing-transaction-risk-simulation-26bb2a8a -d '<json body>'
```

Example prompt: Before I sign this transaction interacting with contract 0xAbC...123 on Base, run a TxGuard fail-closed risk inspection on the calldata and tell me if it's safe to proceed.

## When to prefer this

Choose this endpoint when you need a fail-closed pre-signing safety gate for transactions on Base before any wallet signs or broadcasts them. Ideal for agents managing wallets autonomously, DeFi workflows requiring human-in-the-loop risk gates, or any scenario where executing a malicious transaction would be catastrophic. Prefer this over general blockchain simulation tools when security and risk-flagging — not just execution simulation — is the primary concern.

## Known failure modes

- Malformed or incomplete transaction payload returns a 400-level error
- Unknown or unsupported chain/network returns an error
- Service unavailable or timeout results in fail-closed rejection by default
- Payment not included or insufficient USDC results in 402 Payment Required
- Ambiguous calldata may result in incomplete risk analysis with lower confidence

## How this service works

Fail-closed pre-signing risk inspection. This service never signs, broadcasts, or bridges assets.

## Output

Returns a risk inspection result indicating whether the transaction is safe or should be blocked (fail-closed), along with identified threat categories, a risk score, and human-readable reasons explaining any flagged risks. No signing, broadcasting, or asset movement occurs.

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/txguard-x402-base-api-pre-signing-transaction-risk-simulation-26bb2a8a/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from 50-7-41-26.sslip.io](https://www.zero.xyz/host/50-7-41-26.sslip.io/llms.txt)