Feature Flags vs Branch Deploys

Feature flags and branch deploys are two strategies for managing in-progress features. Feature flags let you merge incomplete features to main with the feature hidden behind a runtime toggle. Branch deploys isolate incomplete features on separate branches deployed to staging environments.

Feature Flags Enable Trunk-Based Development

With feature flags, all developers commit to the main branch continuously. Unfinished features are wrapped in flags that are off by default. This eliminates long-lived feature branches, reduces merge conflicts, and enables continuous integration.

When the feature is ready, flip the flag on — first for internal users, then a percentage of customers, then everyone. If something goes wrong, flip it off instantly without redeploying.

The Flag Debt Problem

Every feature flag adds a conditional code path. If not cleaned up promptly, flags accumulate, creating a tangled web of conditional logic. Testing becomes harder because every combination of flags is a potential state. Disciplined flag hygiene is essential.

Branch Deploys: Simpler but Limited

Branch deploys are conceptually simpler: create a branch, deploy to preview, merge when ready. No conditional logic, no flag management service, no cleanup required. But they do not support gradual rollouts, A/B testing, or instant rollback.

For more on deployment strategies, see our concepts library and system design interview guide. See pricing for full access.

The Bottom Line

Use feature flags for mature teams practicing continuous delivery with gradual rollouts. Use branch deploys for small teams with simple release processes where flag management overhead is not justified.