Let’s Encrypt launched its first publicly-trusted certificate on September 14, 2015, marking the beginning of a significant shift in web security. Over the past decade, it has grown to be the largest certificate authority, issuing billions of certificates and standardizing the ACME protocol, which is now widely adopted across the server ecosystem. By late 2025, Let’s Encrypt was issuing around ten million certificates daily, with a goal of protecting nearly one billion active websites. The organization emphasizes the importance of HTTPS encryption over sheer issuance numbers, showcasing how the percentage of encrypted web connections has risen from below 30% to around 80% globally, and nearly 95% in the U.S. Milestones in Let’s Encrypt’s journey include reaching one million certificates issued in March 2016, and significant growth in daily issuance volumes, particularly supported by integrations with platforms like SquareSpace and Shopify. The team has continuously added features such as wildcard support and internationalized domain name support. In terms of infrastructure, they've upgraded their systems to handle increasing data volumes, moving from Gigabit to 25-gig Ethernet. This evolution reflects the growing demands on their services as they become integral to Internet security. Behind the scenes, Let’s Encrypt has navigated complex PKI engineering challenges to ensure their certificates are widely accepted. Their efforts include managing cross-signatures and developing their own root CA certificates. The organization has engaged with various standards bodies to influence the public key infrastructure landscape. Despite striving for a future where certificate management is seamless for users, the risk of being taken for granted exists. Recognition of the service's value is vital for ongoing support, and Let’s Encrypt continues to be acknowledged through awards and community sponsorships.