This task is one section of Eight software practices that keep business apps reliable, with 7 related tasks on one page.
1. Default it off
The new behavior should be invisible until the flag is on. Deploy that and confirm the old path still works.
2. Turn it on for one user or one test
Enable the flag only for the account you will check. Walk the new path once and write down what you saw.
3. Turn it off
Disable the flag without deploying. The old path should return immediately. If you need a deploy to undo it, it is not a flag.
4. Delete the flag later
When the feature is the default for everyone, remove the flag and the old branch. A permanent flag is a second product.
5. Frequently asked questions
Is a flag a substitute for a backup?
No. It only switches behavior. Take a backup when the change writes data you cannot undo.
Can every feature be flagged?
Flag the ones you may need to turn off. A database migration still needs its own plan.
Who may turn the flag on?
Name those people. An unused flag that anyone can flip is an incident.
6. Related articles and next steps
Treat the checks below as the acceptance test for the change. Names of libraries can vary; the behavior to prove does not.