Let's Encrypt

Let's Encrypt is a nonprofit certificate authority that issues publicly trusted TLS certificates through an automated process.

Format
Security & Encryption
Updated
Updated
Glossary Security & Encryption
Let's Encrypt Aliases: ACME certificate authority.

Definition

Let's Encrypt is a nonprofit certificate authority that issues publicly trusted TLS certificates through an automated process.

How it works

Let's Encrypt made HTTPS free and automatic: its ACME protocol lets your server prove control of a domain, fetch a certificate, and renew it on schedule without anyone touching it. The encryption is exactly as strong as any other domain-validated certificate — what you are not getting is organization vetting or a support contract.

Example: A hosting platform can automatically request and renew a certificate for a customer's domain through ACME.

Often confused: Let's Encrypt is a certificate authority — one issuer of certificates, not the TLS protocol itself.

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Sources

Last reviewed 2026-07-19.