We have a new vivarium for him and I wanted to be able to monitor the temperature inside from anywhere. I was thinking of using MQTT and Thingspeak, but a quick search came up with BLYNK!
Blynk is an app that is easy to link to with Arduino / ESP8266. The device sends data to Blynk's server and the app is SO easy to set up and display the data in graphical and text form.
I used info and code from these sources and adapted them to suit.
https://www.instructables.com/id/Simple-Example-ArduinoESP8266DS18B20/
https://www.instructables.com/id/Blynk-Arduino-Multiple-DS18B20-Thermometer-Display/
My code can be found here:
https://github.com/jcwyatt/Viv_Monitor
I have a Heltec ESP8266 with OLED display.
I may change this as I want the project to be battery powered.