Adafruit IO is an IoT service for everyone.
What Hardware to Use
The feather family is a great option for beginners. It’s an inexpensive board, and there are many libraries and examples.
For those interested in using ethernet or doing a more complex project, the raspberry pi is recommended.
How Adafruit IoT Works
There are two main parts. The back and the front end. The back end is where sensor and other data is received. This data can be in REST or MQTT format. There are libraries for Arduino, C/C++, Python, Node.JS, and Golang. The data is stored in time stamped locations called feeds. The front end is the user side. This is where your dashboard is. The dashboard can be used to monitor real time values. You can also push, pull, or push/pull data. This is also where triggers are set up. A trigger is a way to do something when a specific situation occurs. They can be reactive, happens when something else happens, or scheduled, happens at a set interval. You can also set up an IFTTT (If This Than That). This will allow you to make a call, text, tweet, ect when/ if something happens.
Plus Membership
Adafruit IO standard membership is free and is great for beginners and those without a large number of projects. The plus membership allows you to have more data points per minute, longer storage, and unlimited dashboards and feeds. It can be purchased on a monthly or yearly basis. Sign up for Adafruit IO Plus here.
More Information
For more information visit https://www.digikey.com/en/resources/iot-resource-center/videos and watch episode 4. In this video, Lady Ada shows some helpful examples as well as explains the above in further detail.