Create feature flags

Feature flags, also called feature toggles or permission toggles, let you turn certain functionality on and off without deploying code. Flags give you full control over the lifecycle of a feature. You can

• release code without exposing it to users by keeping the flag off.
• gradually roll out a feature to a portion of your user base.
• validate functionality and performance before a full release.

Permissions required to create a flag

To create a flag in Feature Experimentation, you must have Editor or Admin access in at least one environment. This requirement applies whether access is assigned directly or through a team.

If you have Viewer project role, you cannot create flags by default. However, if you are granted elevated environment-level permissions (such as Editor), you can create flags and audiences.

Your ability to create flags also depends on whether your project uses granular permissions.

• If granular permissions are used – Anyone with elevated environment-level access (Editor or above) can create flags.
• If granular permissions are not used – You must have Editor or Admin project role to create flags or audiences.

Create a flag

Go to Flags > Create New Flag.

1. In the Name field, enter a unique name. Valid keys contain alphanumeric characters, hyphens, and underscores, are limited to 64 characters, and cannot contain spaces.

   📘

   Note

   Feature Experimentation automatically assigns a key to the flag based on this name. You use the flag key to implement the flag in your application's code.

   Flag keys cannot be changed after they are created.

2. (Optional) Enter a Description.

3. Click Create Flag to save your flag.

   • Feature Experimentation automatically creates a read-only flag_off variation to use as the control in experiments.
   • Feature Experimentation automatically creates two environments, Production and Development.

Implement the feature flag

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Note

Before implementing the flag, decide how to pass user identifiers to Feature Experimentation. This ensures each user has a consistent experience of the flag being on or off.

See Handle user ids for information.

After you create the flag in the Optimizely Feature Experimentation dashboard, you need to integrate it with your application code. Use the Decide method to enable or disable the flag for a user.

// Decide if user sees a feature flag variation
user := optimizely.CreateUserContext("user123", map[string]interface{}{"logged_in": true})
decision := user.Decide("flag_1", nil)
enabled := decision.Enabled

// Decide if user sees a feature flag variation
var user = optimizely.CreateUserContext("user123", new UserAttributes { { "logged_in", true } });
var decision = user.Decide("flag_1");
var enabled = decision.Enabled;

// Decide if user sees a feature flag variation
var user = await flutterSDK.createUserContext(userId: "user123");
var decideResponse = await user.decide("product_sort");
var enabled = decision.enabled;

// Decide if user sees a feature flag variation
OptimizelyUserContext user = optimizely.createUserContext("user123", new HashMap<String, Object>() { { put("logged_in", true); } });
OptimizelyDecision decision = user.decide("flag_1");
Boolean enabled = decision.getEnabled();

// Decide if user sees a feature flag variation
const user = optimizely.createUserContext('user123', { logged_in: true });
const decision = user.decide('flag_1');
const enabled = decision.enabled;

// Decide if user sees a feature flag variation
$user = $optimizely->createUserContext('user123', ['logged_in' => true]);
$decision = $user->decide('flag_1');
$enabled = $decision->getEnabled();

# Decide if user sees a feature flag variation
user = optimizely.create_user_context("user123", {"logged_in": True})
decision = user.decide("flag_1")
enabled = decision.enabled

// Decide if user sees a feature flag variation
var decision = useDecision('flag_1', null, { overrideUserAttributes: { logged_in: true }});
var enabled = decision.enabled;

# Decide if user sees a feature flag variation
user = optimizely_client.create_user_context('user123', {'logged_in' => true})
decision = user.decide('flag_1')
decision.enabled

// Decide if user sees a feature flag variation
let user = optimizely.createUserContext(userId: "user123", attributes: ["logged_in":true])
let decision = user.decide(key: "flag_1")
let enabled = decision.enabled

For more detailed examples of each SDK, see:

• Android SDK example usage
• Go SDK example usage
• C# SDK example usage
• Flutter SDK example usage
• Java SDK example usage
• Javascript (Browser) SDK example usage
• JavaScript (Node) SDK example usage
• PHP SDK example usage
• Python SDK example usage
• React SDK example usage
• React Native SDK example usage
• Ruby SDK example usage
• Swift SDK example usage

Adapt the integration code in your application. Show or hide the flag's functionality for a given user ID based on the boolean value your application receives.

The Decide method separates code deployment from the decision to show a feature. The flag's rules determine the result. For example, it returns false if the user is assigned to the control or "off" variation in an experiment.

Next steps

To deliver feature flag configurations, see Create flag variations.