Platform engineering is the discipline of designing and building toolchains and workflows that enable self-service capabilities for software engineering organizations in the cloud-native era.

Platform Engineering

I would recommend using a major cloud vendor like AWS/Azure/GCP right from the start. You don't have to build your own Kubernetes platform right away and you can even use their managed Kubernetes offerings to start. The upgrade path is much cleaner than using Heroku and it isn't such a huge leap to have teams simply use an AWS account to do what they need for a while. There is a very well established ecosystem and set of tools for all the major vendors that can help your engineering teams get things done in a way that starts to look very close to the benefits of something like Heroku.

That's my opinion at this point at least.

Some extra tidbits when I posed this to others at Doma:
• Choosing a technology that your team knows well is crucial in very early startups where speed to find product market fit is vital, so use a PaaS if it accomplishes that
• Firebase and equivalent systems that provide a PaaS experience with a clean upgrade path to a cloud vendor are also very attractive