# OnchainExpat x402 Review Check API

> OnchainExpat x402 Review Check API is a paid API for AI agents from x402.onchainexpat.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-13).

Performs a pay-per-request review check using the x402 payment protocol, returning a structured JSON response for content or submission review

## Facts

- Endpoint: POST https://x402.onchainexpat.com/api/x402-review/check
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/onchainexpat-x402-review-check-api-ce1dc42f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_UFPiTHA9byUnkkQNedHu4

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 onchainexpat-x402-review-check-api-ce1dc42f -d '<json body>'
```

Example prompt: Can you run a review check on this text I submitted — 'The product arrived on time and worked perfectly, highly recommend' — and tell me whether it passes validation?

## When to prefer this

Use this endpoint when you need a lightweight, pay-per-use review validation check that integrates with the x402 micropayment protocol at $0.01 USDC per call, ideal for automated pipelines that need on-demand content review without subscription overhead

## Known failure modes

- Missing or malformed request body returns a 400 error
- Insufficient x402 payment or unpaid request returns a 402 Payment Required response
- Invalid USDC payment amount triggers payment failure
- Service unavailability or internal error returns a 500 response
- Empty or null content field may result in a validation error

## How this service works

Pay-per-request AI, crypto, proxy, and utility APIs using x402 protocol

## Output

Returns a structured JSON object containing the outcome of the review check, including status and relevant metadata about the evaluated content

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "endpoint_url"
 ],
 "properties": {
  "endpoint_url": {
   "type": "string",
   "description": "Full URL of the x402 endpoint to check, including https:// scheme (e.g. 'https://api.example.com/api/x402-tools/weather/current')"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "score": {
   "type": "integer"
  },
  "issues": {
   "type": "array"
  },
  "compliant": {
   "type": "boolean"
  },
  "endpoint_url": {
   "type": "string"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/onchainexpat-x402-review-check-api-ce1dc42f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.onchainexpat.com](https://www.zero.xyz/host/x402.onchainexpat.com/llms.txt)