Monitoring temperature & other parameters with Wireless Sensor Tags, InfluxDB and Grafana

I have been looking for something that would enable monitoring the temperature — among other metrics — in my apartment. I wanted something that:

  1. enables temperature monitoring in multiple rooms
  2. has small sensors
  3. has reasonable battery life
  4. provides some sort of an API to access the measurements

… and there was of course the price & the security aspect as well.