Many Therads in Local Server

Helo Together,
i instaled my local server on an x86 server with atom D2500. It works together with FHEM / Radicale CALDAV and Blynk on DEBIAN Lite NetInst.
As is see on htop blynk genrates many subthreads.
So my question is it normal for this condition. I had 5 project and about 6-10 devices connected to.
See picture:

The Threads dosen´t generate CPU load.


That’s totally fine. Blynk server uses separate thread pools for blocking operations like email, push, tweet, reports, history graph data reading, etc. This done to avoid blocking of the server if one of the subsystem goes down. For example, email service could be not available - in that case thread pool will be filled with "email tasks’ and will stop accept new mails, why all other subsystems will continue to work.