# OnchainExpat x402 Review Endpoint

> OnchainExpat x402 Review Endpoint is a paid API for AI agents from x402.onchainexpat.com, paid per call via x402, $0.25/call, status unknown (last checked 2026-09-15).

Submit a review or feedback object to the x402-powered review endpoint for processing via pay-per-request protocol

## Facts

- Endpoint: POST https://x402.onchainexpat.com/api/x402-review/endpoint
- Price: $0.25/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/onchainexpat-x402-review-endpoint-571fa917
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_y6489I8UkrvSF_McpfCEb

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-endpoint-571fa917 -d '<json body>'
```

Example prompt: Submit a review to the OnchainExpat x402 review endpoint — I want to evaluate this endpoint and post my review data, paying the $0.25 USDC per-request fee via the x402 protocol.

## When to prefer this

Choose this endpoint when you need to submit a review or evaluation payload to the OnchainExpat x402 ecosystem using the x402 micropayment protocol with USDC. Prefer this over traditional REST review APIs when operating in a crypto-native, pay-per-request agent workflow where each call is settled on-chain.

## Known failure modes

- Payment not provided or insufficient USDC balance — returns 402 Payment Required
- Invalid or malformed review payload — returns 400 Bad Request
- x402 payment protocol handshake failure — returns payment error
- Endpoint temporarily unavailable — returns 503 or timeout
- Missing required fields in request body — returns validation error

## How this service works

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

## Output

A JSON response confirming the review was processed, potentially including review status, confirmation details, or evaluation output for the submitted review payload.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "agent_id",
  "endpoint_url",
  "feedback_auth_signature"
 ],
 "properties": {
  "chain": {
   "type": "string",
   "description": "Chain where agent is registered (default: base)"
  },
  "agent_id": {
   "type": "integer",
   "description": "ERC-8004 agent ID"
  },
  "endpoint_url": {
   "type": "string",
   "description": "Full URL of the x402 endpoint to review, including https:// scheme (e.g. 'https://api.example.com/api/x402-tools/weather/current')"
  },
  "feedback_auth_signature": {
   "type": "string",
   "description": "Pre-authorization signature from the agent"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "score": {
   "type": "integer"
  },
  "metrics": {
   "type": "object"
  },
  "tx_hash": {
   "type": "string"
  },
  "scan_url": {
   "type": "string"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/onchainexpat-x402-review-endpoint-571fa917/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)