[emmet]

You have to do it every time you use WhatsApp web. Not for each message, but it's an unwanted ceremony nonetheless.

[mahouse]

No. It's only the first time. Then the key is stored in the browser forever (or, at least, for a very long time)

[binxbolling]

Not for me. It's every time, even though I can see right in the app my exact computer & browser it still wants me to re-scan.