Firebase Remote Config

Change the behavior and appearance of your web client or server without publishing an app update, at no cost, for unlimited daily active users.

Firebase Remote Config is a cloud service that lets you change the behavior and appearance of your client app or server without requiring users to download an app update. When using Remote Config, you create in-app default values that control the behavior and appearance of your application. Then, you can later use the Firebase console or the Remote Config backend APIs to override in-app default values for all Remote Config API consumers or for segments of your user base. Your app or server implementation controls when updates are applied, and it can frequently check for updates and apply them with a negligible impact on performance.

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Key capabilities

Quickly release changes to your app's user base

You can make changes to your app's default behavior and appearance by changing parameter values remotely. For example, you could use a Remote Config parameter as a feature flag to change your app's layout or color theme to support a seasonal promotion, with no need to publish an app update.

Customize your app for segments of your user base You can use Remote Config to provide variations on your app's user experience to different segments of your user base by app version, language, Google Analytics audience, and imported segment.
Use Remote Config personalization to automatically and continuously customize your app for individual users and optimize for strategic goals Use machine learning to continuously tailor individual user experience to optimize for goals like user engagement, ad clicks, and revenue—or any custom event you can measure with Google Analytics—with Remote Config personalization.
Iteratively roll out new features to targeted segments of your user base and compare against an automatically-provisioned control group Use Remote Config rollouts to release targeted updates using parameter values as feature flags, gradually releasing new functionality to your users. Determine release stability and success by comparing Crashlytics and Google Analytics results between the group receiving your rollout value and an equal-sized control group.
Run A/B tests to improve your app You can use A/B Testing and random percentage targeting with Google Analytics to A/B test improvements to your app across different segments of your user base to validate improvements before rolling them out to your entire user base.

How does it work?

Remote Config includes a client library that handles important tasks like fetching parameter values and caching them, while still giving you control over when new values are activated so that they affect your app's user experience. This lets you safeguard your app experience by controlling the timing of any changes.

We recommend adding real-time Remote Config functionality to your fetch logic to automatically fetch the latest Remote Config parameter values as soon as they're published.

The Remote Config client library get methods provide a single access point for parameter values. Your app fetches values from Remote Config using the same logic it uses to get in-app default values, so you can add the capabilities of Remote Config to your app without writing a lot of code.

To override in-app default values, you use the Firebase console or the Remote Config backend APIs to create parameters with the same names as the parameters used in your app. For each parameter, you can set a default value in Remote Config to override the in-app default value, and you can also create conditional values to override the in-app default value for app instances that meet certain conditions.

Remote Config also provides a server client library in the Firebase Admin Node.js SDK v12.1.0+. Your server implementations can use this to fetch values from server-specific templates stored by Remote Config. Learn more at Use Remote Config in server environments.

To learn more about parameters, conditions, and how Remote Config resolves conflicts between conditional values, see Remote Config Parameters and Conditions.

Implementation path

Instrument your app with Remote Config Define which aspects of your app's behavior and appearance you want to be able to change using Remote Config, and translate these into the parameters that you will use in your app.
Set default parameter values Set the in-app default values for Remote Config parameters using setDefaults() and, optionally, download your Remote Config template defaults.
Add logic to fetch, activate, and get parameter values Your app can safely and efficiently fetch parameter values from the Remote Config backend periodically and activate those fetched values. Real-time Remote Config lets your apps fetch updated values as soon as a new Remote Config version is published without the need for polling.

You can write your app without worrying about the best time to fetch values, or even whether any server-side values exist.

Your app uses get methods to get the value of a parameter, similar to reading the value of a local variable defined in your app.

(As needed) Update default and conditional parameter values in Remote Config

You can define values in the Firebase console or the Remote Config backend APIs to override in-app default values. You can do this before or after you launch your app, because the same get methods access in-app default values and values fetched from the Remote Config backend. See Remote Config templates and versioning to learn more about managing and updating Remote Config parameters and values.

(As needed) Update default parameter values in your app Whenever you update your app, you should synchronize its default parameter values with the Remote Config backend. You can quickly download a file of default values in XML, property list (plist), or JSON format to update your app using the REST API and Firebase console. For more information, see Download Remote Config template defaults.
Use A/B Testing and Remote Config personalization to customize user experience and determine the best parameter values to achieve your goals. After you implement Remote Config in your app, you can use it to experiment, extend, and update your app with enhanced features like A/B Testing and Remote Config personalization.

Policies and limits

Note the following policies:

  • Don't use Remote Config to make app updates that should require a user's authorization. This could cause your app to be perceived as untrustworthy.
  • Don't store confidential data in Remote Config parameter keys or parameter values. Remote Config data is encrypted in transit, but end users can access any default or fetched Remote Config parameter that is available to their app instance.
  • Don't attempt to circumvent the requirements of your app's target platform using Remote Config.

Remote Config parameters and conditions are subject to certain limits. To learn more, see Limits on parameters and conditions.

Note the following limits:

  • A Firebase project can have 2000 Remote Config parameters per template type (client or server), which are subject to length and content limits detailed in Limits on parameters and conditions.

  • Firebase stores up to 300 lifetime versions of your Remote Config templates per template type (client or server). This 300 version lifetime limit includes stored version numbers for deleted templates. See Templates and versioning for details.

  • You can have up to 24 running A/B experiments and Remote Config rollouts combined.

Looking to store other types of data?

  • Cloud Firestore is a flexible, scalable database for mobile, web, and server development from Firebase and Google Cloud.
  • Firebase Realtime Database stores JSON application data, like game state or chat messages, and synchronizes changes instantly across all connected devices. To learn more about the differences between database options, see Choose a database: Cloud Firestore or Realtime Database.
  • Firebase Hosting hosts global assets, including the HTML, CSS, and JavaScript for your website as well as other developer-provided assets like graphics, fonts, and icons.
  • Cloud Storage stores files such as images, videos, and audio as well as other user-generated content.

Next steps