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feature flag
Ship the code dark. Turn it on for some people. Turn it off without a rollback of the whole site.
What is feature flag?
A feature flag is a runtime switch in front of a behaviour. The code is in production; the experience is not, until the flag says so.
Why does feature flag matter when vibe coding?
Vibe coding ships straight to everyone. A flag lets you merge incomplete work behind a door. It is not a substitute for tests; it is a substitute for praying.
How do you do feature flag?
New risky UI behind a flag, off by default, on for you. Kill the flag once it is the only path. Flags that live forever are another settings app.
How do you ask a model for feature flag?
Put (feature) behind a feature flag, off by default. Do not gate it only in the UI; the API must refuse too. Do not invent a whole flag admin in this slice.
What goes wrong with feature flag?
A flag checked only in React. The API still does the new thing. That is not a flag. That is a costume.