# PapaCasper SSL Certificate Checker

> PapaCasper SSL Certificate Checker is a paid API for AI agents from papacasper.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-15).

Checks the SSL/TLS certificate for a given hostname, returning certificate validity, expiry, and related details

## Facts

- Endpoint: POST https://papacasper.com/mcp/pay/ssl_cert_check
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/papacasper-ssl-certificate-checker-abafd362
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_iqIYzdMr70QjR7yzzcZXI

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-ssl-certificate-checker-abafd362 -d '<json body>'
```

Example prompt: Can you check the SSL certificate for papacasper.com and tell me when it expires and whether it's currently valid?

## When to prefer this

Use this endpoint when you need a quick, lightweight check of a single domain's SSL/TLS certificate status — especially useful for automated monitoring, pre-deployment validation, or diagnosing HTTPS errors. Prefer this over full SEO audit tools when you only need certificate-specific data rather than a broad site health report.

## Known failure modes

- Invalid or unreachable hostname returns connection error
- Non-TLS port returns no certificate data
- Self-signed or expired certificate may return error or flagged status
- Hostname with no scheme/path required — passing full URL may cause parse failure
- Timeout if host is slow to respond on the specified TLS port

## 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 a structured object containing details about the SSL/TLS certificate for the specified hostname, including validity status, expiration date, issuer information, and any detected issues with the certificate.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "hostname"
 ],
 "properties": {
  "port": {
   "type": "number",
   "description": "TLS port to connect to (default 443)"
  },
  "hostname": {
   "type": "string",
   "description": "Hostname to check, e.g. papacasper.com (no scheme/path)"
  }
 }
}
```

## Response schema (JSON Schema)

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

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/papacasper-ssl-certificate-checker-abafd362/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)