Founder of ToolJet here. ToolJet can be used for building public-facing apps but our focus is only on internal tools. Building public-facing apps will require more design customisation options, a built-in database that will scale well, payments/subscription features, user management features, etc. Right now our goal is to make it easier for developers to build internal tools quickly with the help of drag and drop application builder and the ability to connect to all the possible data sources with less code.