# What is Feature Flag?

> A switch that turns code paths on or off per customer without a deploy.

Canonical: https://www.decimal.app/glossary/feature-flag · Last reviewed: 2026-09-23

A feature flag lets teams enable functionality for some accounts, regions, or percentages of users while it's off for others. Flags are used for gradual rollouts, betas, and kill switches.

## Why it matters

Flags mean two customers on the same version can see different behavior. That's a common reason support can't reproduce an issue on a test account.

## Best practices

1. Make flag state visible to support. Agents should see which flags an account has on.
2. Clean up old flags. Stale flags add hidden branches that nobody remembers.
3. Log flag evaluations. So investigations can tell which path a request took.

## How Decimal helps

Decimal reads config and flag tools like LaunchDarkly during an investigation, so differences between accounts show up as evidence.

## Related terms

- [Cannot Reproduce](https://www.decimal.app/glossary/cannot-reproduce): The status a ticket gets when engineering can't make the bug happen on their side.
- [Regression](https://www.decimal.app/glossary/regression): A bug where something that used to work stops working after a change.
- [Hotfix](https://www.decimal.app/glossary/hotfix): An urgent fix shipped outside the normal release cycle.

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