Providing expiration notifications costs Let’s Encrypt tens of thousands of dollars per year

Not doubting them, but I don’t understand how that’s possible.

Storing the email addresses and expiration dates takes an irrelevant amount of storage space, even if they had billions of cutomers.

Sending the emails should also not cost thousands, even if a significant amount of customers regularly let their certificates expire (which hopefull isn’t the case).

So where are the tens of thousands of yearly costs coming from?

This website is a lot more specific about the data used for fingerprinting.

It also lets you see whether two seperate visits can be correlated (or if your fingerprint is sufficiently randomized each time).

https://abrahamjuliot.github.io/creepjs/