A while back, @Alexander-Krause introduced a mocked environment using basic express routing. It's turned out to be very useful during development, since it's no longer required to have the actual backend services running and has also exposed bugs in the backend implementation due to inconsistencies in the backend and mocked implementation of certain endpoints.
There have been some drawbacks however, which made implementing these mocked endpoints rather difficult, e.g., storing data s.a. user records. This especially became clear when implementing the mocked endpoints for the user service. Processing JSON API data and especially responding with a JSON API serialized response is rather difficult and becomes an extra effort for the developer.
Fortunately, there is a good mock library for Ember called EmberCLI Mirage, which we could use. It makes defining endpoints easy and comes with a database to store and query records from. It automatically detects the existing models used by ember-data and let's you create records for a certain model and insert it into the database. Mirage supports JSON API and de-/serializes data itself. To create some initial data, it allows defining factories, which can be used to create a list of records. What's also a nice feature is that Mirage can be used in tests. So one could easily create a couple users and test whether they are rendered correctly in the user list.
After spending a some hours using the library, it seems very easy to use and a good fit for ExplorViz.