SSL/TLS Certificate Inspector
Inspect a domain's SSL/TLS certificate — issuer, expiry, SANs, cipher suite.
GET
/v1/certificate
curl "https://dns.toolkitapi.io/v1/certificate?domain=github.com"
import httpx
resp = httpx.get(
"https://dns.toolkitapi.io/v1/certificate?domain=github.com",
)
print(resp.json())const resp = await fetch("https://dns.toolkitapi.io/v1/certificate?domain=github.com", {
});
const data = await resp.json();
console.log(data);# See curl example
Response
200 OK
{
"domain": "github.com",
"issued_to": "github.com",
"issuer": "DigiCert Inc",
"serial_number": "0A:06:30:42:7F:5B:2C:EF:F5:2D:47:33:44:82:E5:51",
"valid_from": "2024-03-07T00:00:00",
"valid_until": "2025-03-12T23:59:59",
"days_remaining": 187,
"expired": false,
"subject_alt_names": ["github.com", "www.github.com"],
"signature_algorithm": "sha256WithRSAEncryption",
"protocol_version": "TLSv1.3",
"cipher": "TLS_AES_128_GCM_SHA256",
"key_size": 2048,
"query_time_ms": 145.9
}Try It Live
Live Demo
Response
Description
Inspect a domain's SSL/TLS certificate — issuer, expiry, SANs, cipher suite.
How to Use
1
1. Pass the domain in the `domain` parameter. 2. Optionally set `port` if the service runs on a non-standard port (default: 443). 3. Check `days_remaining` and `expired` for certificate health.
About This Tool
SSL/TLS Certificate Inspector connects to a domain and inspects its certificate. It returns the issuer, validity dates, days until expiry, Subject Alternative Names (SANs), protocol version, cipher suite, and key size.
Why Use This Tool
- Certificate monitoring — Track expiry dates across your domains
- Security audit — Verify TLS version, cipher strength, and key size
- Compliance — Ensure certificates meet organizational requirements
- Troubleshooting — Debug SSL errors by inspecting the actual certificate
Frequently Asked Questions
Can I check certificates on non-standard ports?
Yes — set the `port` parameter (e.g. `port=8443` for an alternative HTTPS port).
Does this validate the certificate chain?
The API inspects the presented certificate. Chain validation is implicit in the TLS handshake.
Start using SSL/TLS Certificate Inspector now
Get your free API key and make your first request in under a minute.