I thought I'd best post my link here to my Arduino Library for connecting to the OctoPrint API. You can download the library within the Arduino IDE under Library manager (search for "octoprint") or via the GitHub page - https://github.com/chunkysteveo/OctoPrintAPI.
It's been a long work in progress, but i'd love to get people's feedback on it, and the next features to add to it. There seems to be a number of WiFi monitors popping up on the internet now to monitor your 3D printer via OctoPrint, so thought it best to make people aware of my existing API library.
It works well using a WiFi chip like the ESP8266 or ESP32 and is just a core library for you to access the OctoPrint API and retrieve (and send!!) data from your printer. What you do with the data is up to you - LED status, OLED display, Relay, buzzer, Alexa, ITTT, Telegram bot.... go wild - i'd love to hear your ideas! There's a couple of example scripts to get you started too.
All the best,