Let’s Encrypt x Shopify: Securing the Web 4.5 Million Domains at a Time - Shopify

This post details Shopify's transition to using Let's Encrypt as its primary Certificate Authority for issuing and renewing TLS certificates for merchant domains. It highlights the challenges of programmatic certificate management with previous providers, the benefits of Let's Encrypt's ACME protocol for automation, and the successful implementation of a system capable of provisioning and renewing certificates for millions of domains within hours, significantly improving responsiveness for emergency rotations.