# agentsvc.io SSL Certificate Checker

> agentsvc.io SSL Certificate Checker is a paid API for AI agents from agentsvc.io, paid per call via x402, $0.009/call, status unknown (last checked 2026-10-10).

Checks the SSL/TLS certificate details for a given domain, returning validity, issuer, expiry, protocol, and fingerprint information.

## Facts

- Endpoint: POST https://agentsvc.io/api/v1/proxy/ssl-check?utm_source=zero.xyz
- Price: $0.009/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-10
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agentsvc-io-ssl-certificate-checker-cc20b835
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_6JW55AqpcYi9TKt0yXqzg

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 agentsvc-io-ssl-certificate-checker-cc20b835 -d '<json body>'
```

Example prompt: Can you check the SSL certificate for api.example.com on port 443 and tell me if it's valid and how many days are left before it expires?

## When to prefer this

Choose this endpoint when you need a quick, per-call SSL certificate inspection without setting up infrastructure. Ideal for one-off checks, agent-driven monitoring workflows, or when you need structured certificate metadata (expiry, issuer, SAN, fingerprint) rather than a raw TLS handshake. Preferred over manual openssl commands or browser inspection when results must be parsed programmatically by an agent.

## Known failure modes

- Domain not found or DNS resolution fails — returns an error object
- Connection refused on specified port — returns connection error
- Certificate chain is broken or self-signed — may still return data but valid:false
- Timeout if the remote server is slow to respond
- Invalid domain format (e.g. includes 'https://') — returns validation error

## How this service works

86 APIs for AI agents: web scraping and crawling to Markdown, AI summaries, data extraction and cited answers, screenshots and PDF, PDF, OCR and document conversion, news, paper and developer search and more, paid per call with USDC on Base, Solana, Polygon or Arbitrum via x402. No account, no API key, free sample on every service.

## Output

Returns a JSON object with the domain, port, whether the certificate is currently valid, the issuer organization, subject CN, TLS protocol version, valid-from and valid-to timestamps, days remaining until expiry, serial number, subject alternative names (SANs), and SHA-256 fingerprint.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "port": {
   "type": "integer",
   "default": 443,
   "description": "Port to check (default: 443)"
  },
  "domain": {
   "type": "string",
   "description": "Domain to check SSL for (e.g. 'github.com', 'api.example.com'). Do not include https://"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "data": {
   "port": 443,
   "valid": true,
   "domain": "github.com",
   "issuer": "DigiCert Inc",
   "subject": "CN=github.com",
   "protocol": "TLSv1.3",
   "valid_to": "2025-03-07T23:59:59.000Z",
   "valid_from": "2024-03-07T00:00:00.000Z",
   "serial_number": "0a:bc:12:...",
   "days_remaining": 156,
   "subject_alt_names": [
    "github.com",
    "www.github.com"
   ],
   "fingerprint_sha256": "AB:CD:EF:..."
  },
  "success": true
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agentsvc-io-ssl-certificate-checker-cc20b835/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agentsvc.io](https://www.zero.xyz/host/agentsvc.io/llms.txt)