A feature toggle is a runtime switch that controls whether a feature is active for a given user, without deploying new code. The term is a synonym for feature flag. Both refer to the same mechanism: a conditional in your code that checks a configuration value to decide which experience a user sees.
Martin Fowler's 2010 taxonomy popularized "feature toggle" and categorized toggles by lifespan and purpose (release toggles, experiment toggles, ops toggles, permission toggles). The categories remain useful. The terminology has shifted. "Feature flag" is now the dominant term in engineering practice, in vendor documentation, and in Confidence.
Why do two terms exist?
The mechanism was invented independently by multiple teams and described with different names. "Feature toggle," "feature flag," "feature switch," and "feature gate" all appeared in engineering literature between 2009 and 2013. As the practice matured, "feature flag" won the naming war. Most modern platforms, including Confidence, LaunchDarkly, and Statsig, use "feature flag" as the primary term.
If you're searching for information or evaluating tools, treat the terms as interchangeable. The underlying concept is identical: decouple deployment from release by wrapping a feature in a conditional that can be changed at runtime.