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---
stage: none
group: Development
info: "See the Technical Writers assigned to Development Guidelines: https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments-to-development-guidelines"
---
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# Feature flags in development of GitLab
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## When to use feature flags
Starting with GitLab 11.4, developers are required to use feature flags for
non-trivial changes. Such changes include:
- New features (e.g. a new merge request widget, epics, etc).
- Complex performance improvements that may require additional testing in
production, such as rewriting complex queries.
- Invasive changes to the user interface, such as a new navigation bar or the
removal of a sidebar.
- Adding support for importing projects from a third-party service.
- Risk of data loss
In all cases, those working on the changes can best decide if a feature flag is
necessary. For example, changing the color of a button doesn't need a feature
flag, while changing the navigation bar definitely needs one. In case you are
uncertain if a feature flag is necessary, simply ask about this in the merge
request, and those reviewing the changes will likely provide you with an answer.
When using a feature flag for UI elements, make sure to _also_ use a feature
flag for the underlying backend code, if there is any. This ensures there is
absolutely no way to use the feature until it is enabled.
## How to use Feature Flags
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Feature flags can be used to gradually deploy changes, regardless of whether
they are new features or performance improvements. By using feature flags,
you can determine the impact of GitLab-directed changes, while still being able
to disable those changes without having to revert an entire release.
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Before using feature flags for GitLab development, review the following development guides:
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NOTE:
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The feature flags used by GitLab to deploy its own features **are not** the same
as the [feature flags offered as part of the product ](../../operations/feature_flags.md ).
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For an overview about starting with feature flags in GitLab development,
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use this [training template ](https://gitlab.com/gitlab-com/www-gitlab-com/-/blob/master/.gitlab/issue_templates/feature-flag-training.md ).
Development guides:
- [Process for using features flags ](process.md ): When you should use
feature flags in the development of GitLab, what's the cost of using them,
and how to include them in a release.
- [Developing with feature flags ](development.md ): Learn about the types of
feature flags, their definition and validation, how to create them, frontend and
backend details, and other information.
- [Documenting features deployed behind feature flags ](../documentation/feature_flags.md ):
How to document features deployed behind feature flags, and how to update the
documentation for features' flags when their states change.
- [Controlling feature flags ](controls.md ): Learn the process for deploying
a new feature, enabling it on GitLab.com, communicating the change,
logging, and cleaning up.
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User guides:
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- [How GitLab administrators can enable and disable features behind flags ](../../administration/feature_flags.md ):
An explanation for GitLab administrators about how they can
enable or disable GitLab features behind feature flags.
- [What "features deployed behind flags" means to the GitLab user ](../../user/feature_flags.md ):
An explanation for GitLab users regarding how certain features
might not be available to them until they are enabled.
