SSL & TLS

Two escalating warning levels: below the configured lead time (default 14 days, adjustable 1 to 90 days) a warning, at 3 days or fewer remaining a critical. Only one open expiry alert is active per website at a time; it auto-resolves once remaining validity climbs back above the threshold after the renewal — no duplicate emails across repeated checks. You set the lead time under Settings → Notifications.

The maximum permitted TLS certificate lifetime is shrinking in steps (CA/Browser Forum SC-081): 200 days since 03/2026, at most 100 days from 03/2027, at most 47 days from 03/2029. The SSL tab shows the total lifetime (`cert_lifetime_days`), the current limit and the next step. Certificates longer than 100 days suggest manual issuance without ACME and are flagged as `cert_renewal_risk` — with an alert (on by default, can be switched off under Settings → Notifications) advising a switch to automatic renewal (ACME, e.g. Let's Encrypt) before the next step takes effect.

The chain is validated at TLS handshake time against the system CA store (Mozilla root bundle, `verify_peer=true`). Missing intermediates (browsers show OK but mobile/email clients fail), expired, revoked or hostname-mismatched certificates trigger a handshake error and are marked `is_valid=false`. This case is the most urgent and fires its own critical alert (`ssl_invalid`) — independent of the expiry lead time, because a broken handshake leaves no remaining-validity figure to compute. The website scan additionally extracts chain length (`chain_length`) and root CA and shows them in the tab.

TLS version (e.g. TLS 1.3), the active cipher suite, key type (RSA / EC), key length (`key_bits`) or ECC curve (`key_curve`) are captured by the website scan and shown in the SSL tab. All values come from the real TLS handshake during the fetch — not a theoretical enumeration of all ciphers. The daemon continuous monitoring only stores the negotiated protocol version (e.g. `TLSv1.3`) over time and keeps it in the history table.

HTTP Strict Transport Security is evaluated separately in the Security tab (max-age, includeSubDomains, preload). Must-Staple (RFC 7633) is detected directly on the certificate and shown as a badge in the SSL tab.

Validation type (DV / OV / EV) and SAN coverage are shown as badges; the full SAN list of all covered hostnames is expandable. Wildcard certificates are flagged separately.

Every SSL check is saved as a row in the history table: checked-at timestamp, issuer, protocol, valid-until and status. For ranges beyond 30 days the view condenses to one row per day (the last check of each day, up to 90 days). The history automatically detects two event types: an issuer change (`issuer_change`) and a renewal whenever the valid-until date (`expires_at`) shifts. A 90-day bar colours each check by remaining validity: green from 30 days, amber between 14 and 30 days, red below.