📱 Mobile

Remote Config

remote config · remote configuration · firebase remote config · server-driven config · app config service

Definition

Remote config is a cloud service for managing an app's behavioural parameters without publishing an update; it changes functionality and content instantly for all users or a chosen segment.

Why remote config exists

Publishing a mobile app update in the App Store or Google Play takes anywhere from a few hours to a
few days of review. Yet most changes in an e-commerce app need no code change at all — they are
configuration: banner copy, promotion thresholds, switching a new feature on for part of the
audience.

Remote config solves that: the parameters live in the cloud and are delivered to the app at launch.
Changing a banner or a free-delivery threshold takes minutes, with no release.

How remote config works

Cloud service: parameter "promo_banner_text" = "20% off until Friday"
       ↓ (at app launch)
Device: the parameter cache is refreshed (TTL 12 hours)
       ↓
The UI reads the parameter value → shows the current banner

When a value changes on the server, everyone receives the update at their next app launch, or on an
explicit fetch and activate.

Typical e-commerce scenarios

Scenario	Parameter	Without remote config
A promotional banner	`promo_banner_text`, `promo_end_date`	An app release
The free-delivery threshold	`free_shipping_threshold: 25`	A release plus store review
Switching a new feature on for 10%	`new_checkout_enabled: true` (a 10% segment)	A full A/B through a release
An emergency kill switch	`feature_payments_v2: false`	A hotfix plus review

Segmentation in remote config

Remote config can deliver different values to different segments:

By app version — older builds receive the old parameters, newer builds the new ones.
By platform — iOS and Android see different configurations.
By audience — people in a particular region, or with particular behaviour.
By random percentage — 10% of users receive the test value (the built-in A/B).

Remote config and feature flags together

Remote config often complements a full feature-flag server: remote config for parameters that must
reach mobile fast, feature flags (LaunchDarkly, Unleash) for server-side logic and more elaborate
targeting rules.

Tip: always set default values in the app’s own code in case remote config is unavailable — no
network, an expired TTL. The app must work correctly on defaults without depending on the cloud
service.

Frequently asked questions

How does remote config differ from a feature flag?

A feature flag is the general concept of switching functionality on and off. Remote config is a specific implementation aimed at mobile apps, with the emphasis on parameters — not only booleans but strings, numbers and JSON. Feature flags are usually managed on the server and need a server call. Remote config is cached on the device and works offline.

How quickly do remote config changes reach users?

Firebase Remote Config is cached on the device with a default TTL of 12 hours. The app fetches updates at launch or on an explicit call. For urgent changes, such as an emergency feature kill switch, either shorten the TTL or use realtime updates. At the next app launch the person is guaranteed to receive the current values.

Can you A/B test through remote config?

Yes — Firebase Remote Config has built-in A/B testing: different user segments receive different parameter values and the results are compared on a target metric such as retention or conversion. It is convenient for testing with no code change at all — configuration only.

How safe is it to keep logic in remote config?

Remote config suits configuration parameters, not business-critical or sensitive logic. Config values sit on the device and can be extracted from memory. Never keep API keys, pricing rules or the terms of a valuable promotion in remote config — otherwise they can be forced on the client.