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Advanced Topic 40 of 50 DevOps & Tooling

Feature Flags

Toggling features at runtime without redeploying.

How it works

A feature flag is a condition in code that turns behavior on or off at runtime without a new deployment. Flags can be simple booleans or rules targeting users, percentages, regions or plans, evaluated by a service such as LaunchDarkly, Unleash or a config file. They separate deploying code from releasing it, enabling gradual rollouts, A/B experiments, kill switches for risky features and testing in production with internal users. Flags fall into release, experiment, operational and permission types, each with a different lifespan.

Where it is used

Teams use them to ship incomplete work safely behind a flag, roll out to one percent of users first and disable a failing feature instantly.

Common pitfall

Old flags left in code create dead branches and combinations nobody tests, and flag service outages can break evaluation. Give each flag an owner and expiry, define safe defaults and remove flags after rollout.

Where it fits in the course

Feature Flags is topic 40 of 50 in DevOps & Tooling, rated Advanced. It follows GitOps. The next topic is Trunk-Based Development.

Practice and explore

How to study this topic

  1. Read the explanation above and restate the definition in your own words.
  2. Open the interactive lesson and answer its mini quiz.
  3. Read the common pitfall, then write a short example that avoids it.
  4. Check your understanding in the DevOps & Tooling quiz, and revisit the topic if you miss a question.

Frequently asked questions

What is Feature Flags?
Toggling features at runtime without redeploying. It belongs to DevOps & Tooling and is an advanced-level topic.
Where do people use Feature Flags?
Teams use them to ship incomplete work safely behind a flag, roll out to one percent of users first and disable a failing feature instantly.
What is the most common mistake with Feature Flags?
Old flags left in code create dead branches and combinations nobody tests, and flag service outages can break evaluation.
What should I learn before this topic?
Start with GitOps, the topic just before it in DevOps & Tooling.
How can I practice it?
Answer the mini quiz in the interactive lesson, then take the DevOps & Tooling quiz.
Is Feature Flags hard to learn?
It is an Advanced topic. Expect to read the explanation more than once and to connect it with earlier topics. Working through a small example by hand helps most.
How long does it take to learn Feature Flags?
Most learners can read the explanation and finish the interactive lesson in under an hour. Fluency comes from applying the idea, so plan a few short practice sessions with the quiz.
Which topics are related to Feature Flags?
GitOps, Trunk-Based Development, Secrets Management are closely connected. The full list is in the related topics section of this page.
What should I study after Feature Flags?
Continue with Trunk-Based Development, the next topic in DevOps & Tooling.

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