Let's Encrypt Languages English Català Čeština Dansk Deutsch Greek Español Suomi Français עברית Magyar Bahasa Indonesia Italiano 日本語 한국어 Polish Português do Brasil Русский සිංහල Srpski Svenska தமிழ் Thai Türkçe Українська Tiếng Việt 简体中文 繁體中文 Skip navigation links Documentation Get Help Blog Donate Become a Sponsor Current Sponsors & Funders Get Involved Donate About Us Let's Encrypt Frequently Asked Questions (FAQ) Policy and Legal Repository Service Status Statistics Contact Careers Annual reports Internet Security Research Group (ISRG) Donate Now Donate Now Encryption for Everybody A nonprofit providing free TLS certificates to more than 700M700M websites. Get Started Sponsor Explore our work to improve security and privacy Our 2025 Annual Report highlights the progress we've made toward a better Internet. Read the Annual Report → From our blog August 11, 2026 Going Back to Our Roots: A Little Piece of Let's Encrypt History ISRG Root X1 now on a t-shirt Read more → June 3, 2026 A Post-Quantum Future for Let's Encrypt Let’s Encrypt is preparing its certificates for a post-quantum future through a new approach called Merkle Tree Certificates. Read more → April 10, 2026 The difficulty of making sure your website is broken Building automation to keep our test certificates reliably invalid. Read more → See all our blog posts Free, Automated TLS Certificates Getting started Let's Encrypt is a Certificate Authority that provides free TLS certificates, making it easy for websites to enable HTTPS encryption and create a more secure Internet for everyone. Let's Encrypt is a project of the nonprofit Internet Security Research Group. Ready to begin? + Start securing your websites with free SSL/TLS certificates from Let's Encrypt. In order to get a certificate for your website's domain, you have to demonstrate control over the domain. Let's Get Started → Documentation + Learn about our certificate issuance process and best practices. Read Documentation → ACME Clients + Choose from our recommended ACME clients to automatically manage your certificates. Browse ACME Clients → Get help from the Let's Encrypt Community + Join our community forum for technical assistance and knowledge sharing with experts, volunteers, and ISRG staff. Visit the Forum → Global impact made possible by generosity Support Encryption for Everybody Your donation helps keep Let's Encrypt free and accessible to millions of websites around the world. Join us in securing the Internet, one site at a time. Every contribution makes a difference, whether you're an individual or a company. Donate Now Leading Through Sponsorship Companies who rely on or value our work to encrypt the Web can financially support Let's Encrypt. Join companies big and small to make this work possible! Learn about Sponsorship More ways we're improving security and privacy Did you know Let's Encrypt has two sibling projects? Let's Encrypt and these two projects are operated by Internet Security Research Group (ISRG), a 501(c)(3) public benefit organization focused on making the Internet more secure and privacy-respecting. Focused on memory safety in critical Internet infrastructure through the use of memory safe programming languages. Visit Prossimo A privacy-respecting system for collecting and aggregating metrics, built on Multi-Party Computation. Visit Divvi Up Major Sponsors and Funders Diamond Level Platinum Level Gold Level Silver Level Learn about Sponsorship Let's Encrypt is a free, automated, and open Certificate Authority brought to you by the nonprofit Internet Security Research Group (ISRG). Read all about our nonprofit work this year in our 2025 Annual Report. Legal Address 548 Market St, PMB 77519 San Francisco, CA 94104-5401 USA Send all mail or inquiries to: PO Box 18666 Minneapolis, MN 55418-0666 USA Subscribe for email updates about Let's Encrypt and other ISRG projects © 2026 Internet Security Research Group GitHub LinkedIn Terms Privacy Policy Trademark Policy