Quarkus Feature Flags

A lightweight and extensible feature flag extension for Quarkus. Turn features on and off, roll out gradually, or switch behavior based on context — all with a simple and intuitive API.

Quick Start

Add the dependency to your project:

<dependency>
    <groupId>io.quarkiverse.flags</groupId>
    <artifactId>quarkus-flags</artifactId>
    <version>LATEST</version>
</dependency>

Define a feature flag:

quarkus.flags.runtime."my-feature".value=true

Use it in your code:

@Inject
Flags flags;

void doWork() {
    if (Flag.get("my-feature").isEnabled()) {
        // static access — no injection needed
    }
    if (flags.isEnabled("my-feature")) {
        // Flags central entry point
    }
}

Features

• Simple API — inject Flags, use static Flag.get(), or declare flags with @RegisterFlag on static fields and methods.
• Multiple value types — boolean, string, integer, and decimal.
• Built-in providers — define flags via Quarkus config, declarative @RegisterFlag annotations, or the in-memory repository for testing.
• Built-in evaluators — time span, composite, and variant evaluators out of the box.
• Caching — built-in in-memory cache for flag provider results with configurable TTL and per-provider overrides; extensible via the FlagCache SPI, with an optional quarkus-flags-cache module backed by Quarkus Cache.
• Extensible SPI — implement custom FlagProvider or FlagEvaluator to fit your needs.
• Hibernate ORM and Hibernate Reactive — load flags from a database.
• Security — evaluate flags based on the current SecurityIdentity, including percentage-based rollouts.
• Qute — use flags directly in templates.
• Cron — enable flags on a schedule using CRON expressions.
• OpenFeature — integrate with the OpenFeature standard.

Documentation

Full documentation is available at https://docs.quarkiverse.io/quarkus-flags/dev/.