Let's Encrypt

Let's Encrypt is a free, automated, and open certificate authority (CA) provided by the Internet Security Research Group (ISRG). It allows website owners to obtain trusted SSL/TLS certificates for their domains, enabling secure HTTPS connections, without the usual cost or manual administrative…

Key facts

First appeared
2015
Category
technology
Problem solved
Let's Encrypt solved the long-standing problem of expensive, complex, and manually intensive SSL/TLS certificate acquisition and renewal. Before Let's Encrypt, securing a website with HTTPS was a barrier for many due to the costs associated with commercial Certificate Authorities and the intricate, often confusing, process of generating Certificate Signing Requests (CSRs), validating domain ownership, and installing certificates.
Platforms
macOS (for development and specific server setups), Any server environment capable of running an ACME client and serving web content, Linux (server-side, most common for Certbot), Windows (via WSL or specific client integrations)

Related technologies

Notable users

  • Millions of individual website owners and bloggers
  • Hosting providers and CDNs (e.g., Cloudflare, Akamai)
  • Large enterprises and technology companies (e.g., WordPress.com, Automattic, OVHcloud, DigitalOcean)
  • Small and medium businesses