Author of privapps Notebook, I just had first release couple of days ago. It was my side project and I didn't expect to monetize it, the notebook project is more like a missionary project.

https://news.ycombinator.com/item?id=26289683

I think e2e encryption and share is not new, especially compare to the privatebin, which has been out there for quite a long time, and it is mature with a lot of features, such as docker / K8s deployment.

If Droppler want to success, it might need to do slack integration, SSO and customize work. Since the space is very crowd there.

In addition, it can be very easy to be used for other purposes.

Edit: I read your site again, it is like try to make e2e encryption as a SaaS platform, for fast app development. This direction is kind of overlapping with vault: https://spring.io/projects/spring-vault

Many cloud platform like AMZ, GCP have secrets management services, it can be a hard battle.