feature flags

Long-lived branches pile up merge debt until integration becomes a gamble. There is a named technique that ships a three-month refactor in releasable increments, and its final step is deletion.

Redeploying the old tag reverses code and nothing else. What separates staff-level answers is a per-change map of what rolls back in seconds, what rolls back in days, and what only moves forward.

The honest mechanics of merging to trunk many times a day: flags, fast CI, trunk locks, and the conditions under which you should not run it at all.

Deployment and release are two decisions, not one. The flag patterns that buy you instant reversibility, and the retirement discipline most teams skip.

Flags sit on the request path of everything, so a slow flag service is a site-wide outage waiting to happen. Local snapshots, propagation numbers, and audit trails are what interviewers dig for.