Feature Flag

Also called: Feature toggle, Feature switch

TL;DR

A switch in code that lets a team turn a feature on or off for specific users or segments without redeploying.

Feature flags decouple the act of shipping code from the act of releasing functionality. A team can deploy a half-finished feature behind a flag, enable it for internal users, then progressively roll it out to 1%, 10%, and 100% of customers based on what telemetry shows.

Beyond release safety, flags enable experimentation (A/B variants), entitlement gating (paid-tier features), and incident response (instant rollback by flipping a flag). Mature engineering organizations treat flag hygiene, naming, ownership, and retirement, as a first-class discipline.

Worked example

A team ships a new checkout flow behind a LaunchDarkly flag, enables it for 1% of US traffic, watches conversion stay flat and error rate stay <0.05%, then ramps to 10%, 50%, 100% over 7 days, with the ability to instant-rollback any cohort if something regresses.

Common pitfalls

•Letting flags accumulate forever instead of retiring them when stable.
•Using flags as long-term branching instead of progressive rollout.
•Hiding behavior changes behind flags so customers can't be supported predictably.

When this shows up in a pitch deck

Rarely cited explicitly, but referenced indirectly when teams describe progressive rollout, dogfooding, or experimentation velocity.

Related terms

A/B Test

A controlled experiment that compares two versions of a feature, page, or flow to determine which produces a better outcome.

Dogfooding

Using your own product internally for real workflows so the team experiences the same friction and bugs the customer does.

Lean Startup

A methodology for building startups under uncertainty using rapid Build-Measure-Learn cycles instead of long product plans.

Onboarding

The structured first-use experience that takes a new user from sign-up to the first moment of real value.

Use Feature Flag in your next pitch deck

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