# api402x Echo – Connectivity Test Endpoint

> api402x Echo – Connectivity Test Endpoint is a paid API for AI agents from api402x.com, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-10).

Returns a simple liveness ping (ok: true + timestamp) to verify the api402x service is reachable and the x402 payment flow is working correctly.

## Facts

- Endpoint: GET https://api402x.com/echo?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-10
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/api402x-echo-connectivity-test-endpoint-eac39383
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_b3dWqgHd9dxvq3vvAP8To

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 api402x-echo-connectivity-test-endpoint-eac39383
```

Example prompt: Ping the api402x echo endpoint to confirm the service is up and my x402 USDC payment is processing correctly — just return whether it responded with ok and what timestamp it reported.

## When to prefer this

Use this endpoint specifically when you need to verify that the api402x x402 payment pipeline is functioning end-to-end before committing to higher-value data calls. It is the lowest-cost ($0.01 USDC) way to confirm your agent's USDC wallet, payment header generation, and network path to api402x are all working. Not suitable for retrieving actual market or onchain data.

## Known failure modes

- Payment rejected: x402 payment header missing or USDC balance insufficient — returns 402 Payment Required
- Service unavailable: api402x server down — returns 5xx or connection timeout
- Invalid request: malformed properties parameter — may return 400 Bad Request
- Network unreachable: DNS or routing failure before payment even attempted

## How this service works

Onchain- and crypto-market data for trading AI agents. Payment via x402 (USDC, exact scheme).

## Output

Returns a JSON object with an 'ok' boolean (true when the service is healthy) and a 'ts' ISO 8601 timestamp reflecting the server's current time. A successful response confirms both network reachability and that the x402 USDC micropayment ($0.01) was accepted.

## Request schema (JSON Schema)

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

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true,
  "ts": "2026-08-05T12:00:00.000Z"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/api402x-echo-connectivity-test-endpoint-eac39383/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api402x.com](https://www.zero.xyz/host/api402x.com/llms.txt)