2026-06-29
What is Let's Encrypt — the free CA that automates HTTPS
Let's Encrypt = a free, automated TLS certificate authority (CA). The ACME protocol verifies domain control automatically, so issuance and renewal are hands-off. Certificates are short-lived (90 days) by design — to shrink the window of a key compromise and force automation. The biggest real-world incident isn't an attack but a renewal that broke without anyone noticing → cert expired → browser warning → users bounce. So monitor expiry. This site itself uses Let's Encrypt via Caddy's automatic TLS.