FeatureFlags.app

Feature Management Dashboard for .NET

Deploy anytime. Release when you're ready.
Keep your IFeatureManager, FeatureGate, and feature tag helper code, change flags without redeploying, and skip the Azure subscription.

Why Developers Choose FeatureFlags.app

🔧 Built for Microsoft's Feature Management libraries

IFeatureManager, IFeatureManagerSnapshot, [FeatureGate], and the <feature> tag helper work as they always have. Flags use Microsoft's built-in Targeting and TimeWindow filters, so there is no new evaluation model to learn.

🚀 Release features without redeploying

Gradually roll out changes, turn off problematic features without a deploy, and schedule features with time windows. Changes reach your apps within your refresh interval (15 minutes by default).

☁️ No Azure subscription required

Your app can run on Azure, AWS, GCP, or your own servers. FeatureFlags.app is a hosted service, so there is nothing to set up or run besides the client package.

⚡ Evaluated inside your app

Flags are read from an in-memory copy that refreshes in the background, so checks never wait on the network, and your app keeps using the last-known-good copy during an outage. Set the refresh interval to balance network calls against how quickly changes reach your apps.

🔒 Your users' data stays in your app

Because evaluation happens in your app, user identities and evaluation results are never sent to FeatureFlags.app. The client only downloads your flag definitions.

Stop Redeploying Just to Toggle Features

Modern teams shouldn't redeploy applications just to:
  • Disable broken features.
  • Release gradually.
  • Test production safely.

From a Redeploy to a Dashboard

Your flag-checking code doesn't change. Only where the flags come from does.

Before: flags in appsettings.json

{
  "FeatureManagement": {
    "NewCheckout": true
  }
}

Changing a flag means editing the file and redeploying.

After: flags in the dashboard

using Acmi.FeatureFlags.Client;

var builder = WebApplication.CreateBuilder(args);
builder.AddFeatureFlags();
{
  "FeatureFlags": {
    "ApiBaseEndpoint": "https://featureflags.app/api/",
    "ApiKey": "[from user secrets or environment variables]"
  }
}

Change a flag in the dashboard and your apps pick it up within their refresh interval (15 minutes by default, configurable).

Your code stays the same

[FeatureGate("NewCheckout")]
public IActionResult Checkout() => View();

// or check the flag yourself
if (await featureManager.IsEnabledAsync("NewCheckout")) {
    // new checkout
}
<feature name="NewCheckout">
    <a href="/checkout">Check out</a>
</feature>

How It Works

  1. Configure: Create feature flags and API keys through the web UI.
  2. Integrate: Add the client library to your ASP.NET Core applications (.NET 10 or later).
  3. Control: Easily toggle features on/off, or create more complex rules.

Feature Comparison

FeatureFlags.app LaunchDarkly Azure App Config ConfigCat
Works with Microsoft.FeatureManagement ✅ ❌ ✅ ❌
Percentage rollouts ✅ ✅ ✅ ✅
User targeting ✅ ✅ ✅ ✅
Audit logs ✅ Enterprise plan ✅ ✅
Price for 100 flags $25/month Flags are unlimited; priced per service connection ($10/month each after the first 5) About $36/month (Standard store, $1.20/day); flags are not metered $110/month (Pro)
Environments included Unlimited 3 on the free plan; unlimited on paid One store per environment, or labels 2 on the free plan; 3 on Pro
Apps / service connections included Unlimited 5 on the free plan; $10/month each after that No app limit; request quotas apply 2 products on the free plan; 3 on Pro
Azure subscription required ❌ ❌ ✅ ❌
Export flags as Microsoft.FeatureManagement JSON ✅ ❌ ✅ ❌
Self-hostable ❌ ❌ (self-hosted Relay Proxy only) ❌ ✅ (Proxy and private-cloud plan)

Last verified: October 9, 2026, against each vendor's public pricing and documentation. Plans and prices change, so check the vendor before you decide.

Built For Modern .NET Teams

  • Development teams seeking a simple, no-frills feature flag solution.
  • Teams already using Microsoft.FeatureManagement that want to change flags without editing config files and redeploying.
  • Teams without Azure that don't want to adopt an Azure subscription just to manage flags.

What if it goes away?

A hosted service should be easy to leave, so:

  • The client is MIT-licensed. See it on GitHub.
  • Flags use Microsoft's standard format, so they load in plain Microsoft.FeatureManagement.
  • Export any environment to standard JSON on every plan, even while you are over your flag limit.
  • Service health is public on the status page.

Featured On

Ready to Get Started?

Check out the Quick Start Guide to add it to your ASP.NET Core application.