You need the stack servant tool that can be downloaded like this in Unix systems:

curl -sSL https://get.haskellstack.org/ | sh

For further instructions about Stack please go to https://docs.haskellstack.org/en/stable/README/

This is a very minimal example of a project that uses

• servant to specify a REST API,
• servant-server to implement a server,
• hspec and servant-client for the test-suite.
• persistent for database management.
• servant-auth and servant-auth-server for JWT authentication.

To set up the project and run the test-suite, do:

stack setup
stack test --fast

to reload the code (after making changes) and run the tests again.

To run the app, do:

stack build
stack exec servant-persistent-template

I tried to create a Clean architecture, complete domain testing and split commands/queries to make it easy to extend in the future.