Introduction

Flagstack is a feature flag management platform built for Ruby and Rails teams. It provides a powerful UI for managing flags and a simple SDK that works seamlessly with Flipper.

What is Flagstack?

Flagstack provides everything you need to safely roll out features to your users:

• Feature Flags — Toggle features on and off without deploying code
• Progressive Rollouts — Gradually release features to a percentage of users
• Environment Inheritance — Manage flags across development, staging, and production
• Targeting — Enable features for specific users, groups, or percentages
• Audit Logging — Track every change with full accountability

Quick Example

Here's how simple it is to check a feature flag in your Rails app:

class DashboardController < ApplicationController
  def show
    if Flagstack.enabled?(:new_dashboard, current_user)
      render :new_dashboard
    else
      render :legacy_dashboard
    end
  end
end

The flag can be managed entirely from the Flagstack dashboard — no code changes needed to toggle it on or off.

How it Works

Flagstack uses a simple architecture that keeps your app fast:

1. Configure your API token in your Rails app
2. Flag state syncs automatically to a local cache
3. Checks are instant — no network requests on every check
4. Changes propagate within seconds of updating in the dashboard

Next Steps

Ready to get started? Here's where to go next: