# PapaCasper WebSocket Endpoint Check

> PapaCasper WebSocket Endpoint Check is a paid API for AI agents from papacasper.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-14).

Tests whether a given WebSocket URL is reachable and responsive

## Facts

- Endpoint: POST https://papacasper.com/mcp/pay/websocket_endpoint_check
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/papacasper-websocket-endpoint-check-45a7d571
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_RbXItegTmc6Oo6zgGehHh

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 papacasper-websocket-endpoint-check-45a7d571 -d '<json body>'
```

Example prompt: Can you check if my WebSocket server at wss://example.com/socket is up and accepting connections?

## When to prefer this

Use this endpoint when you need a quick, lightweight check on whether a specific WebSocket URL is live and accepting connections — especially useful in CI/CD pipelines, pre-flight checks, or debugging real-time infrastructure. Prefer this over general HTTP uptime checkers when the target protocol is WebSocket (ws:// or wss://).

## Known failure modes

- Invalid or malformed WebSocket URL (non-wss/ws scheme) — returns error
- Target host unreachable or DNS resolution failure
- Connection timeout if the server does not respond
- TLS/SSL certificate errors on secure wss:// endpoints
- Payment not accepted or insufficient USDC balance for the x402 call

## How this service works

A hosted MCP server exposing utility tools any AI agent can call over HTTP — page-to-markdown, SEO audits, robots/sitemap checks, and more.

## Output

Returns an object indicating whether the WebSocket URL is reachable and connectable, including connection status and any relevant error or response details from the handshake attempt.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "url"
 ],
 "properties": {
  "url": {
   "type": "string",
   "description": "WebSocket URL to test, e.g. wss://example.com/socket"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object"
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/papacasper-websocket-endpoint-check-45a7d571/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from papacasper.com](https://www.zero.xyz/host/papacasper.com/llms.txt)