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 work in our Annual Report.
Visit letsencrypt.org → RSS feedOn Hacker News Jun 2015 – Jun 2026
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Our goal with Let’s Encrypt is to get the Web to 100% HTTPS. We’d like to give a quick progress update. Let’s Encrypt has issued more than 5 million certificates in total since we launched to the general public on December 3, 2015. Approximately 3.8 million of those are active, meaning unexpired and unrevoked. Our…
Today we turned off our Online Certificate Status Protocol (OCSP) service, as announced in December of last year. We stopped including OCSP URLs in our certificates more than 90 days ago, so all Let’s Encrypt certificates that contained OCSP URLs have now expired. Going forward, we will publish revocation information…
We’re happy to share today that Facebook is the newest Gold sponsor of Let’s Encrypt. Facebook has taken multiple important steps to support and advance encryption this year, and we are glad to see Let’s Encrypt as the latest example. According to Alex Stamos, Chief Security Officer at Facebook, “Making it easier for…
Let’s Encrypt is proud to introduce Sunlight, a new implementation of a Certificate Transparency log that we built from the ground up with modern Web PKI opportunities and constraints in mind. In partnership with Filippo Valsorda, who led the design and implementation, we incorporated feedback from the broader…
The keys and certificates that will underlie Let’s Encrypt have been generated. This was done during a key ceremony at a secure facility today. The following objects were created: Key pair and self-signed cert for the ISRG root Key pair and certificate for the ISRG root’s OCSP Key pairs and certificates for two Let’s…
On a normal day Let’s Encrypt issues nearly two million certificates. When we think about what essential infrastructure for the Internet needs to be prepared for though, we’re not thinking about normal days. We want to be prepared to respond as best we can to the most difficult situations that might arise. In some of…
Update: January 15, 2026 Six-day and IP address certificates are now generally available. See 6-day and IP Address Certificates are Generally Available for details. This year we will continue to pursue our commitment to improving the security of the Web PKI by introducing the option to get certificates with six-day…
Every night, right around midnight (mainly UTC), a horde of zombies wakes up and clamors for … digital certificates! The zombies in question are abandoned or misconfigured Internet servers and ACME clients that have been set to request certificates from Let’s Encrypt. As our certificates last for at most 90 days…
Let’s Encrypt will enter Public Beta on December 3, 2015. Once we’ve entered Public Beta our systems will be open to anyone who would like to request a certificate. There will no longer be a requirement to sign up and wait for an invitation. Our Limited Beta started on September 12, 2015. We’ve issued over 11,000…
Since its inception, Let’s Encrypt has been sending expiration notification emails to subscribers that have provided an email address to us via the ACME API. This service ended on June 4, 2025. The decision to end the service is the result of the following factors: Over the past 10 years more and more of our…
Let’s Encrypt will be reducing the validity period of the certificates we issue. We currently issue certificates valid for 90 days, which will be cut in half to 45 days by 2028. This change is being made along with the rest of the industry, as required by the CA/Browser Forum Baseline Requirements, which set the…
NGINX and Let's Encrypt share a common vision of an open and secure web. Now, with built-in support for ACME, the world's most popular web server, reverse proxy and ingress controller for Kubernetes can simplify certificate management for everyone. From the home lab to scaled-out, mission-critical enterprise…
This letter was originally published in our 2022 annual report. The past year at ISRG has been a great one and I couldn’t be more proud of our staff, community, funders, and other partners that made it happen. Let’s Encrypt continues to thrive, serving more websites around the world than ever before with excellent…
On Wednesday, March 13, 2024, Let’s Encrypt generated 10 new Intermediate CA Key Pairs, and issued 15 new Intermediate CA Certificates containing the new public keys. These new intermediate certificates provide smaller and more efficient certificate chains to Let’s Encrypt Subscribers, enhancing the overall online…
Update: Feb. 5 2020 The Let’s Encrypt CT logs are now included in approved log lists and are usable by all publicly-trusted certificate authorities. Today we are announcing a new Certificate Transparency log called Oak. The Oak log will be operated by Let’s Encrypt and all publicly trusted certificate authorities will…
The Let’s Encrypt team is excited to announce that ACME Renewal Information (ARI) is live in production! ARI makes it possible for our subscribers to handle certificate revocation and renewal as easily and automatically as the process of getting a certificate in the first place. With ARI, Let’s Encrypt can signal to…
This month, Let’s Encrypt is turning on new infrastructure to support revoking certificates via Certificate Revocation Lists. Despite having been largely supplanted by the Online Certificate Status Protocol for over a decade now, CRLs are gaining new life with recent browser updates. By collecting and summarizing CRLs…
At Let’s Encrypt we’re always looking for ways to improve the security and integrity of the Web PKI. We’re proud to launch multi-perspective domain validation today because we believe it’s an important step forward for the domain validation process. To our knowledge we are the first CA to deploy multi-perspective…
Since we announced Let’s Encrypt we’ve often been asked how we’ll ensure that we don’t issue certificates for phishing and malware sites. The concern most commonly expressed is that having valid HTTPS certificates helps these sites look more legitimate, making people more likely to trust them. Deciding what to do here…
This is a historic blog post at this point. Please see our certificate lifetime documentation for the current status of certificate lifetimes. We’re sometimes asked why we only offer certificates with ninety-day lifetimes. People who ask this are usually concerned that ninety days is too short and wish we would offer…