Disclaimer: I'm VP of Engineering for software consultancy focused on IoT. We work with startups, midcap and several fortune 500s. I agree vendor lock in must

Disclaimer: I'm VP of Engineering for software consultancy focused on IoT. We work with startups, midcap and several fortune 500s. I agree vendor lock in must be avoided. I also disagree that Open Source is the best approach in all situations. Mosquito and Raspberry Pi are fine for smaller projects, but if you're going to push 100M or a billion messages, you're better off leveraging a IaaS solution like AWS IoT Core. At least, until you have a dedicated 24/7 opps team that can triage and support the solution. The trick is to create the right abstractions and architectures to migrate your solutions off of AWS and onto another solution: Azure, your own, etc.