IoT Platforms

7 competitive open source IoT frameworks:

Open Source Cloud Platforms

Other interesting projects to look at.

Thingsboard is a relatively new open-source IoT platform for data collection, processing, visualization, and device management. You can deploy it in the cloud or on-premises.

As one of Thingsboard authors, I can say that the main project idea is:

https://opensourceforu.com/2018/10/the-top-open-source-iot-platforms-for-developers/