# Mercer x402 Ping (Hub Probe)

> Mercer x402 Ping (Hub Probe) is a paid API for AI agents from x402.lucidcove.org, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Returns a timestamped pong JSON after a $0.001 USDC micropayment, serving as an end-to-end connectivity and settlement canary for x402 clients.

## Facts

- Endpoint: GET https://x402.lucidcove.org/v1/ping
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/mercer-x402-ping-hub-probe-a98dac33
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_bZnKhf7uFwnPW0YGUn1up

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 mercer-x402-ping-hub-probe-a98dac33
```

Example prompt: Send a $0.001 USDC ping through my x402 client to confirm the full payment and settlement flow is working end-to-end — I need to see a timestamped pong back.

## When to prefer this

Use this endpoint specifically when you need to verify that an x402 micropayment stack (client, wallet, and facilitator) is wired together correctly end-to-end. It is purpose-built as a cheap ($0.001 USDC) settlement canary, making it ideal for smoke tests, CI/CD health checks, and debugging payment pipeline issues before invoking more expensive x402-enabled services.

## Known failure modes

- Payment not included or malformed x402 header — server returns 402 Payment Required
- Insufficient USDC balance — payment rejected before a pong is returned
- Wrong facilitator endpoint configured — request never reaches the server
- Network timeout — no response, indicating connectivity issue downstream
- Invalid wallet credentials — payment authorization fails silently or with a 401/403

## How this service works

Settlement canary: returns a timestamped pong JSON after USDC micropayment. Use to verify x402 client + wallet + facilitator end-to-end.

## Output

A small JSON object containing a 'pong' acknowledgment and a server-side timestamp, confirming that the x402 payment was received and settled, and that the full client-wallet-facilitator pipeline completed successfully.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [],
     "properties": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/mercer-x402-ping-hub-probe-a98dac33/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.lucidcove.org](https://www.zero.xyz/host/x402.lucidcove.org/llms.txt)