# OnChaiNinja MEV Protection & Detection

> OnChaiNinja MEV Protection & Detection is a paid API for AI agents from x402ninnin.vercel.app, paid per call via x402, $3/call, status unknown (last checked 2026-09-11).

Scans a specific on-chain transaction on a given blockchain for MEV (Maximal Extractable Value) activity and protection status

## Facts

- Endpoint: GET https://x402ninnin.vercel.app/api/mev/%7Bchain%7D/%7Btx%7D
- Price: $3/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/onchaininja-mev-detection-fd1060f6
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap__AOPgzdx8zNZJyM3PE5P_

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 onchaininja-mev-detection-fd1060f6
```

Example prompt: Can you check if my transaction 0x4a7b9c2d1e8f3a56b0c9d2e7f4a1b8c3d9e6f2a5 on Base was hit by a sandwich attack or any MEV extraction?

## When to prefer this

Use this endpoint when you need to determine whether a specific transaction hash on Base, Solana, Arbitrum, or another supported chain was subjected to MEV extraction, sandwich attacks, or front-running. Best suited for post-trade analysis or DeFi protection workflows.

## Known failure modes

- Invalid chain identifier returns error or empty result
- Invalid or malformed transaction hash returns error
- Transaction not found on specified chain returns not-found error
- Unsupported chain returns 400 or similar
- Network timeout for slow RPC response
- Payment failure (insufficient USDC) blocks access with 402

## How this service works

Alpha signals, whale tracking, rug scanning, and MEV protection across Base, Solana, Arbitrum, and more.

## Output

Returns a JSON object indicating whether MEV was detected for the specified transaction on the given chain, with a boolean mevDetected field and potentially additional details about the type or severity of MEV activity observed.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "properties": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "mevDetected": false
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/onchaininja-mev-detection-fd1060f6/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402ninnin.vercel.app](https://www.zero.xyz/host/x402ninnin.vercel.app/llms.txt)