You can use this web app as a boilerplate for building your own SaaS product. The app has many common SaaS features, so you can focus on the features that differentiate your product.

As with most boilerplates, this is opinionated about its stack, which features:

React, Material-UI, Next, MobX, Express, Mongoose, MongoDB, Typescript

Here’s the full list of features and the live demo.