Create a flag

Name it

Flag keys are lowercase with dashes, such as checkout-v2. Pick a name that says what the flag changes, not who asked for it.

Choose a default

The default is what the SDK returns when no rule matches, and when Plinth can’t be reached. For a new feature it is almost always false.

Turn it on somewhere safe

Each environment has its own switch. Turn the flag on in development first:

Environment	State	Who sees it
development	on	everyone
staging	on	everyone
production	off	nobody

Flags you no longer need are debt. Plinth marks flags that have been fully on or off for 30 days, and the GitHub integration suggests the clean-up.