Spinner is a development tool that lets you inspect and run queries against an app's database(s) in a convenient web interface.

Install one of the spinner build variants (e.g. ./gradlew installPlayProdSpinner) and run the following adb command:

adb forward tcp:5000 tcp:5000

Then, navigate to localhost:5000 in your web browser.

Magic!

Spinner is just a NanoHttpd server that runs a little webapp in the background. You initialize Spinner in Application.onCreate with a list of databases you wish to let it run queries against. Then, you can use the adb forward command to route the Android device's port to a port on your local machine.

It's a riff on Flipper, a development tool we used to use. It was very useful, but also wildly unstable (at least on Linux).