You can use Remote Config to perform a percentage rollout to slowly expose
your users to new functionality. For this use case, let us say you have a new
search function that is enabled and disabled using a Remote Config
parameter named `new_search_feature_flag`, and you want to begin by rolling it
out to 10% of your installed user base.

To achieve this, edit your `new_search_feature_flag` parameter, add a new
condition, and select **User in random percentage**. Use the slider to set the
random percentage between 0 and 10.

> [!TIP]
> **Tip:** You can use the **Seed** value to create multiple conditions that target specific ranges of the same randomized group of users. See [User in random percentage](https://firebase.google.com/docs/remote-config/client-parameter#user-in-random-percentage) for more information.

![Image moving through the Firebase console GUI steps to perform a percentage rollout on an existing parameter](https://firebase.google.com/static/docs/remote-config/images/RCUC_1_New_Feature_Rollout_1_1.png) Adding parameter for percentage feature rollout

Now, when the `new_search_feature_flag` value is fetched from Remote Config, 10% of randomly selected users receive the value `true`, while the other 90%
receive the value `false`.

When you are satisfied with the stability of the feature in 10% of the user
population, you can increase it to 30%, to 50%, and eventually to 100%
once you have full confidence in the feature.

> [!TIP]
> **Tip:** Be sure to add a [real-time Remote Config listener](https://firebase.google.com/docs/remote-config/ios/real-time.md.txt) to your app to ensure that your feature flag is rolled out (or rolled back) as soon as you modify your template.