We're are developing an open source offering in this space: https://budibase.com . Planning to have an MVP in the summer - at which stage we will also make the source public.

We are more focussed around a tool for building SaaS products, fast. However, we are planning to build a Notion-like app using BudiBase, for management of the project & business.

Sign up for updates if you're interested!

Website is a bit vague on detail right now... a few features:

- Design your own data model: create typed fields, data validation rules, object relationships, indexing & scaling options

- HTTP Api for all CRUD operations, based on your data model

- User Management & User Role definitions

- Generated UI, with the ability to drop in your own UI wherever suits

- Fully pluginable backend, for integrations

- Output is a Single Page Web application, with an HTTP Api & data storage. Web app will be mobile ready (PWA).