Server software · checked November 15, 2026

Is Caddy ready for 100-day and 47-day certificates?

Renews automatically

Caddy’s own certificates renew automatically, so the shorter lifetimes (100 days from March 15, 2027, 47 days from March 15, 2029) are handled for you.

What renews automatically

• renewal_window_ratio defaults to 0.3333: Caddy keeps trying to renew once a third of the lifetime remains. It scans managed certificates every 10 minutes by default and is ARI-aware.[Caddy]
• On errors it retries, switches challenge types, tries the next issuer (Let's Encrypt, ZeroSSL) and backs off for up to 30 days.[Caddy]

What doesn’t

Caddy’s documentation lists no setup that needs manual renewal.

When it renews

When 1/3 of the lifetime remains (default).[Caddy]

What to do, and by when

1. February 10, 2027 · In 87 days
   Let's Encrypt default certificates drop to 64 days[Let's Encrypt 1 (Let's Encrypt — Decreasing Certificate Lifetimes to 45 Days (Dec 2, 2025)), 2 (Let's Encrypt — 64-Day Certificate Lifetimes Coming Feb 2027 (Oct 7, 2026))]
   Nothing to do with default settings.

Steps

1. Keep Caddy updated and leave renewal_window_ratio at its default.
2. Watch the logs for renewal errors.