SSL Certificate Inspector
Inspect a live TLS certificate: subject, issuer, SAN domains, validity window, days to expiry, protocol version, cipher and the full chain length. Read directly from a TLS handshake — the definitive check an agent should run before trusting an API endpoint.
🔌 Server-side tool
This tool runs on the server (it fetches third-party URLs directly and cannot run in your browser). Use the paid JSON API below — the worked examples show real server-side results and refresh automatically.
Worked examples
Non-standard port
GET /api/v1/security/ssl-inspector?domain=smtp.gmail.com&port=465
Result: ✓ Valid — smtp.gmail.com · 66 day(s) left · TLSv1.3 · TLS_AES_256_GCM_SHA384
Machine API (x402)
$0.005 / callThis tool is also a JSON API for AI agents. Requests without payment receive 402 Payment Required plus instructions; agents pay USDC on Base via the x402 protocol — no accounts, no API keys.
GET /api/v1/security/ssl-inspector?domain=agentstoolshub.com HTTP/1.1
Host: agentstoolshub.com
→ 402 (payment required, instructions in headers)
→ 200 (after X-PAYMENT header; JSON body below)
{
"tool": "security/ssl-inspector",
"input": {"domain":"agentstoolshub.com"},
"result": { "value": null, "answer": "" }
}Agent docs: /llms.txt · OpenAPI spec · integration guide
About this tool
Reads the certificate a server actually presents during a TLS handshake — not a cached database: subject and issuer, SAN list, chain, protocol version, cipher suite, fingerprint and the exact days-to-expiry. The pre-flight check for any domain an agent is about to send credentials or payments to.
Frequently asked questions
Does this reject self-signed or invalid certificates?
No — it connects with verification disabled so it can *report* what the server presents (that's the point of an inspector). The chain and issuer output make invalid setups visible.
How is days-to-expiry computed?
From the certificate's notAfter field parsed at request time, in UTC. Under 15 days gets flagged: most CAs recommend renewing at 30 days, and browsers warn at the very end.