Server-side, there is common middleware that both services will need to be implement:

• Authentication (already implemented differently in both relations and inventory)
• Error logging
• Metrics
• ...

To avoid duplicating code and maintenance, these should be factored out to a separate library, which is then imported into both Relations and Inventory.

Both services use the Kratos framework. Ideally, as much as we can is factored out into Kratos itself. We had to write some custom middleware to support streaming endpoints, for example, which we are working on getting upstreamed. This might be an opportunity to try and push that forward so we can use the same implementation for both Inventory & Relations.