My take of - Let's Encrypt uptime and downtimes

I have looked at all historical reports at and the result is covered in a write-up at

I’d be keen to hear any feedback and happy to amend accordingly. What I came up with was:

  • 99.9% uptime if only “total disruptions” are taken into account; and
  • 98% if partial disruptions are included (this goes up to 98.8% for 2017 only)

What surprised me was that the 2-server configuration doesn’t really seem to help much, except for seamless updates. I mention a few things that may be worth to look at but overall, I think guys here can be proud of themselves.

Here’s a couple of charts to bring in some color.

A complete text is at, enjoy

It’s not surprising that the total duration and the number of “partial downtime” incidents are larger than for complete disruptions — you can notice that the chart above goes one order higher, even though it again uses a logarithmic scale. As a result, the overall up-time here was at around 98% at the end of September 2017. If you wonder what it would look like if we skipped the big incident in May 2016, the final up-time would go up to 98.8% in 2017 only.


Thanks, this is an interesting article!

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