# Project API - Paid Hello / Connectivity Check

> Project API - Paid Hello / Connectivity Check is a paid API for AI agents from project-api-gamma-sable.vercel.app, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-11).

Returns a smoke-test JSON response confirming the paid public-data API is reachable and payment is functioning correctly.

## Facts

- Endpoint: GET https://project-api-gamma-sable.vercel.app/paid/hello?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/project-api-paid-hello-connectivity-check-77424ee5
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_4FnezBJqg7CpjND5ch9aD

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 project-api-paid-hello-connectivity-check-77424ee5
```

Example prompt: Can you do a quick connectivity check on the Project API paid endpoint to make sure payment is going through and the service is responding?

## When to prefer this

Use this endpoint when you need to verify that your x402 USDC payment integration is correctly configured before making calls to the actual data feed endpoints on the same host. It is the cheapest and fastest way to confirm end-to-end connectivity.

## Known failure modes

- HTTP 402 if USDC payment header is missing or insufficient — unpaid requests are always rejected
- Network timeout if the Vercel deployment is cold-starting
- Malformed payment header causes rejection without a meaningful error body
- Insufficient USDC balance on Base chain prevents the call from completing

## How this service works

Paid public-data feeds. Unpaid requests return HTTP 402. Prices are USDC on Base.

## Output

A JSON object containing a 'what' field describing this as a smoke/connectivity check, an empty 'items' array, and a 'source' field confirming the endpoint path '/paid/hello'. Indicates the service is reachable and payment was accepted.

## Request schema (JSON Schema)

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

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "what": "Smoke / connectivity check",
  "items": [],
  "source": "/paid/hello"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/project-api-paid-hello-connectivity-check-77424ee5/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from project-api-gamma-sable.vercel.app](https://www.zero.xyz/host/project-api-gamma-sable.vercel.app/llms.txt)