Let's Encrypt

In a recent conversation with a Let’s Encrypt subscriber, we asked them to guess how many people work at ISRG, the nonprofit behind Let’s Encrypt (and Prossimo and Divvi Up). Their guess was about 100; they’d overestimated by 72.5 people. We’re a pretty...

Short-lived and IP address certificates are now generally available from Let’s Encrypt. These certificates are valid for 160 hours, just over six days. In order to get a short-lived certificate subscribers simply need to select the ‘shortlived’ certificate...

This letter was originally published in our 2025 Annual Report.
This year was the 10th anniversary of Let’s Encrypt. We’ve come a long way! Today we’re serving more than 700 million websites, issuing ten million certificates on some days. Most importantly, when we started 39% of page loads on the Internet were encrypted...

On September 14, 2015, our first publicly-trusted certificate went live. We were proud that we had issued a certificate that a significant majority of clients could accept, and had done it using automated software. Of course, in retrospect this was just...