SSL Expiry Check
Fast TLS certificate expiry check: days remaining, issuer, validity window and an expired/expiring-soon flag, read live from a TLS handshake. The cheap monitoring primitive agents should call on a schedule before a cert lapses and an integration breaks.
🔌 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
This site
GET /api/v1/security/ssl-expiry?domain=agentstoolshub.com
Result: ✓ agentstoolshub.com — 85 day(s) left (until 2027-01-10)
A major CDN
GET /api/v1/security/ssl-expiry?domain=cloudflare.com
Result: ✓ cloudflare.com — 49 day(s) left (until 2026-12-04)
A registrar
GET /api/v1/security/ssl-expiry?domain=namecheap.com
Result: ✓ namecheap.com — 85 day(s) left (until 2027-01-09)
Machine API (x402)
$0.002 / 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-expiry?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-expiry",
"input": {"domain":"agentstoolshub.com"},
"result": { "value": 85, "answer": "✓ agentstoolshub.com — 85 day(s) left (until 2027-01-10)" }
}Agent docs: /llms.txt · OpenAPI spec · integration guide
About this tool
The minimal certificate-lifetime check: connect, read notAfter, report days remaining with an expired/expiring flag. Cheap enough to call on a schedule for every domain you depend on — expired certificates are still one of the most common avoidable outages.
Frequently asked questions
ssl-inspector vs this?
ssl-inspector returns the full certificate (SANs, chain, cipher, fingerprint) for a deeper audit; this returns the expiry verdict only, at half the price — the right choice for recurring monitoring.
When should a cert be renewed?
Industry practice is 30 days before expiry. The tool flags anything within 15 days; automated renewals (Let's Encrypt et al.) typically renew at 30.