--- title: When Feature Flags Do And Don’t Make Sense | daily.dev description: Feature flags are a powerful but often overused tool. They make clear sense for A/B testing, managing complex multi-part epics, and situations where binary... canonical: https://daily.dev/posts/when-feature-flags-do-and-don-t-make-sense-nalowqlnq twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: When Feature Flags Do And Don’t Make Sense | daily.dev og:description: Feature flags are a powerful but often overused tool. They make clear sense for A/B testing, managing complex multi-part epics, and situations where binary... og:url: https://daily.dev/posts/when-feature-flags-do-and-don-t-make-sense-nalowqlnq og:image: https://api.daily.dev/og/posts/NaLowqLnQ.png og:image:alt: When Feature Flags Do And Don’t Make Sense og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # When Feature Flags Do And Don’t Make Sense **[Hacker News](https://daily.dev/sources/hn)** · 8 min read · 0 upvotes · 0 comments ## Summary Feature flags are a powerful but often overused tool. They make clear sense for A/B testing, managing complex multi-part epics, and situations where binary rollbacks are impractical (e.g., mobile apps). However, mandating flags for every change as a risk-mitigation strategy is misguided — automated tests, QA, and rollbacks are better alternatives. The real costs of feature flags include combinatorial complexity, accumulated tech debt, and hard-to-detect bugs from stale flags. The KCG financial firm disaster, where dead code behind an old flag contributed to a $500M loss, illustrates the danger. The recommendation is to use feature flags judiciously, not universally. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### What caused the Knight Capital Group trading disaster in 2012? An obsolete feature flag tied to dead code called Power Peg, unused since 2003, was inadvertently re-enabled during a deployment because safety checks had been disabled by a 2005 code change. The dormant functionality ran unchecked in production, causing Knight Capital Group to lose roughly half a billion dollars in about 30 minutes and nearly go bankrupt. _Anyone weighing feature flag risk management can find similar postmortems and engineering lessons curated on daily.dev._ ### When does it make sense to use feature flags in software development? Feature flags make sense for A/B testing to measure business impact of new features, for coordinating complex multi-part epics that span many sub-tasks and pull requests, and when a team lacks control over its own deployments, such as apps combining code from many teams into a single binary. They also help hit specific marketing launch dates while deploying code earlier for stability. _Teams deciding whether to adopt feature flags can compare real-world trade-offs like these on daily.dev._ ### What is Google's recommended approach when a production bug is detected after a release? Google's philosophy is that rollbacks are normal: when an error is found or reasonably suspected in a new release, the releasing team rolls back first and investigates the problem second, rather than attempting a hasty roll-forward fix that might fail or introduce further latent bugs. _Engineers building incident response playbooks can track practices like this via daily.dev._ ## Similar posts on daily.dev - [The Feature Flag Graveyard: How a Safety Net Becomes Technical Debt](https://daily.dev/posts/the-feature-flag-graveyard-how-a-safety-net-becomes-technical-debt-sejgd2oau) · CodeCraft Diary · 16 upvotes · 16 comments - [Configuration flags are where software goes to rot](https://daily.dev/posts/configuration-flags-are-where-software-goes-to-rot-ofqkpk7uc) · Lobsters · 0 upvotes · 0 comments - [How to Implement Feature Flags for Safe and Gradual Rollouts](https://daily.dev/posts/how-to-implement-feature-flags-for-safe-and-gradual-rollouts-6vw4b4ldf) · freeCodeCamp · 0 upvotes · 0 comments - [How to Deploy 10 Times a Day Safely with Feature Flags](https://daily.dev/posts/how-to-deploy-10-times-a-day-safely-with-feature-flags-kxushzxjh) · CodeCraft Diary · 2 upvotes · 0 comments --- Tags: [#cicd](https://daily.dev/tags/cicd), [#technical-debt](https://daily.dev/tags/technical-debt), [#ab-testing](https://daily.dev/tags/ab-testing) [View this post on daily.dev](https://daily.dev/posts/when-feature-flags-do-and-don-t-make-sense-nalowqlnq) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"When Feature Flags Do And Don’t Make Sense","url":"https://daily.dev/posts/when-feature-flags-do-and-don-t-make-sense-nalowqlnq","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/when-feature-flags-do-and-don-t-make-sense-nalowqlnq"},"datePublished":"2026-08-09T05:09:03.598Z","dateModified":"2026-09-14T09:12:18.782Z","description":"Feature flags are a powerful but often overused tool. 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