When you’ve a complicated app then trying out a new idea can be difficult if the existing code gets in the way. Being able to quickly spin up a basic app allows you to try things out and learn quickly. The basic app should have some starter models and data so you can experiment without getting bogged down. Whether it’s pre-configured repo you duplicate, some sort of templating system, or a Makefile it doesn’t matter as long as you can quickly try something out.

The data model doesn’t have to match your domain as long as it has some similar structures. I’ve used Accounts, Transactions, Journal Entries before. Project, Milestone, Task could work too. You don’t need to worry about login, authentication, etc. You can have multiple templates for different languages or frameworks and try out several approaches without having to make an upfront choice.

This is also a good way of explaining a technique to another developer. You can be clear on what you mean without getting bogged down in the details of the main codebase. Or if you don’t understand what they’re proposing you can ask them to show you in the test project.

Do you have anything setup like this? If not how long would it take you to build?