Check SSL certificate expiry, issuer, chain validity, and TLS version for any domain. Monitor your certs via API.
3 free requests/day without API key
https://ssl-check-six.vercel.appX-API-Key: your_key (header) or ?key=your_key (query)Get your free key below/api/ssl?domain=example.comCheck SSL certificate for a given domain. Returns certificate details, validity, and expiry information.
domainstringyesDomain to check (e.g. github.com){
"domain": "github.com",
"valid": true,
"issuer": "DigiCert",
"subject": "github.com",
"sans": ["github.com", "*.github.com"],
"not_before": "2024-03-07T00:00:00Z",
"not_after": "2025-03-12T23:59:59Z",
"days_remaining": 187,
"chain_length": 3,
"protocol": "TLS 1.3",
"serial_number": "123456789"
}// 400 — Bad Request
{ "error": "Missing 'domain' parameter" }
// 401 — Unauthorized
{ "error": "Invalid API key" }
// 422 — Check Failed
{ "error": "SSL check failed: cannot connect to example.com:443" }
// 429 — Rate Limited
{ "error": "Daily limit reached. Upgrade your plan." }Get a free API key for 6 requests/day. No credit card required.
X-API-Key: your_key?key=your_keyStart free. Pay only when you need more.