API: How to get technician key using REST?

API: How to get technician key using REST?

I'm creating a mobile app to manage the assets and was using Servlet API, however since its discontinued I'm moving over to REST.

The issue I am having is trying to get the Technician Key to use the API without making the technician's find it and enter it. How do I get the technician key through REST automatically based on the entered username and password? I'm assuming this can be done since the iOS app does it.

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