VWO Feature Management and Experimentation SDK for React Native

Overview

The VWO Feature Management and Experimentation SDK (VWO FME iOS SDK) enables iOS developers to integrate feature flagging and experimentation into their applications. This SDK provides full control over feature rollout, A/B testing, and event tracking, allowing teams to manage features dynamically and gain insights into user behavior.

Installation

# via yarn
yarn add vwo-fme-react-native-sdk

# via npm
npm install vwo-fme-react-native-sdk

For iOS, install the CocoaPods dependencies by running below command. Supports iOS version 12.0 and above.

cd ios && pod install

Official Documentation

For more detailed documentation, please refer here.

Basic Usage

import { init } from 'vwo-fme-react-native-sdk';

import {
  VWOInitOptions,
  VWOUserContext,
  GetFlagResult,
} from 'vwo-fme-react-native-sdk/src/types';

let vwoClient;

// initialize sdk
useEffect(() => {
  const initializeSDK = async () => {
    const options: VWOInitOptions = { sdkKey: SDK_KEY, accountId: ACCOUNT_ID };
    try {
      vwoClient = await init(options);
      // console.log('VWO init success');
    } catch (error) {
      // console.error('Error initialising', error);
    }
  };

  initializeSDK();
}, []);

// create user context
const userContext: VWOUserContext = { id: 'unique_user_id', customVariables: {key_1: 0, key_2: 1} };

// get feature flag
const flagResult: GetFlagResult = await vwoClient.getFlag('feature_key', userContext);

// check if flag is enabled
const isEnabled = flagResult.isEnabled();

// get the variable value for the given variable key and default value
const variableValue = flagResult.getVariable('feature_flag_variable_key', 'default_value');

// track event for the given event name with event properties
const eventProperties = { 'amount': 99 };
vwoClient.trackEvent('vwo_event_name', userContext, eventProperties);

// send attributes data
const attributes = { attr1: value1, attr2: value2 };
vwoClient.setAttribute(attributes, userContext);

Advanced Configuration Options

To customize the SDK further, additional parameters can be passed to the VWOInitOptions initializer. Here’s a table describing each option:

Parameter	Description	Required	Type	Example
accountId	VWO Account ID for authentication.	Yes	number	123456
sdkKey	SDK key corresponding to the specific environment to initialize the VWO SDK Client. You can get this key from VWO Application.	Yes	String	"32-alpha-numeric-sdk-key"
logLevel	The level of logging to be used.	No	Enum	LogLevel.debug
logPrefix	A prefix to be added to log messages.	No	String	"VWO"
pollInterval	Time interval for fetching updates from VWO servers (in milliseconds).	No	Int64	60000
integrations	To use callback function to handle integration events.	No	Bool	true
cachedSettingsExpiryTime	Expiry time for cached settings in milliseconds.	No	number	3600000
batchMinSize	Minimum size of batch to upload.	No	number	10
batchUploadTimeInterval	Batch upload time interval in milliseconds.	No	Int64	300000

Additional Callbacks

• Integration Callback: Use VWO.registerIntegrationCallback to manage integration events. Refer documentation

• Log Callback: Use VWO.registerLogCallback to capture and handle log events. Refer documentation

Refer to the official VWO documentation for additional parameter details.

User Context

The context object uniquely identifies users and is crucial for consistent feature rollouts. A typical context includes an id for identifying the user. It can also include other attributes that can be used for targeting and segmentation, such as customVariables.

Parameters Table

The following table explains all the parameters in the context object:

Parameter	Description	Required	Type	Example
id	Unique identifier for the user.	Yes	String	'unique_user_id'
customVariables	Custom attributes for targeting.	No	Object	{ age: 25, location: 'US' }

Example

import {  VWOUserContext } from 'vwo-fme-react-native-sdk/src/types';

const userContext: VWOUserContext = { id: 'unique_user_id', customVariables: { age: 25, location: 'US' } };

Basic Feature Flagging

Feature Flags serve as the foundation for all testing, personalization, and rollout rules within FME. To implement a feature flag, first use the getFlag API to retrieve the flag configuration. The getFlag API provides a simple way to check if a feature is enabled for a specific user and access its variables. It returns a feature flag object that contains methods for checking the feature's status and retrieving any associated variables.

Parameter	Description	Required	Type	Example
featureKey	Unique identifier of the feature flag	Yes	String	'new_checkout'
context	Object containing user identification and contextual information	Yes	VWOUserContext	{ id: 'unique_user_id', customVariables: {key_1: 0, key_2: 1} }

Example usage:

import {  VWOUserContext, GetFlagResult } from 'vwo-fme-react-native-sdk/src/types';

const userContext: VWOUserContext = { id: 'unique_user_id', customVariables: {key_1: 0, key_2: 1} };

// get feature flag
const flagResult: GetFlagResult = await vwoClient.getFlag('new_checkout', userContext);

// check if flag is enabled
const isEnabled = flagResult.isEnabled();

if (isEnabled) {
  console.log('Feature is enabled!');

  // get all variables of feature flag
  const allVariables = flagResult.getVariables();

  // get the variable value for the given variable key and default value
  const variableValue = flagResult.getVariable('feature_flag_variable_key', 'default_value');

} else {
  console.log('Feature is not enabled!');
}

Custom Event Tracking

Feature flags can be enhanced with connected metrics to track key performance indicators (KPIs) for your features. These metrics help measure the effectiveness of your testing rules by comparing control versus variation performance, and evaluate the impact of personalization and rollout campaigns. Use the trackEvent API to track custom events like conversions, user interactions, and other important metrics:

Parameter	Description	Required	Type	Example
eventName	Name of the event you want to track	Yes	String	'purchase_completed'
context	Object containing user identification and contextual information	Yes	VWOUserContext	{ id: 'unique_user_id' }
eventProperties	Additional properties/metadata associated with the event	No	Object	{ amount: 49.99 }

Example usage:

const userContext: VWOUserContext = { id: 'unique_user_id' };

vwoClient.trackEvent('purchase_completed', userContext, { amount: 49.99 });

See Tracking Conversions documentation for more information.

Pushing Attributes

User attributes provide rich contextual information about users, enabling powerful personalization. The setAttribute method provides a simple way to associate these attributes with users in VWO for advanced segmentation. Here's what you need to know about the method parameters:

Parameter	Description	Required	Type	Example
attributes	An object containing key-value pairs of attributes to set	Yes	Object	{ 'plan_type': 'premium', 'age': 30, 'isActive': true }
context	Object containing user identification and contextual information	Yes	VWOUserContext	{ id: 'unique_user_id' }

Example usage:

const userContext: VWOUserContext = { id: 'unique_user_id' };

const attributes = { plan_type: 'premium', age: 25 };
vwoClient.setAttribute(attributes, userContext);

See Pushing Attributes documentation for additional information.

Polling Interval Adjustment

The pollInterval is an optional parameter that allows the SDK to automatically fetch and update settings from the VWO server at specified intervals. Setting this parameter ensures your application always uses the latest configuration.

Example usage:

const options: VWOInitOptions = { sdkKey: SDK_KEY, accountId: ACCOUNT_ID, pollInterval: 600000 }; // 10 minutes
vwoClient = await init(options);

Cached Settings Expiry Time

The cachedSettingsExpiryTime parameter allows you to specify how long the cached settings should be considered valid before fetching new settings from the VWO server. This helps in managing the freshness of the configuration data.

Example usage:

const options: VWOInitOptions = { sdkKey: SDK_KEY, accountId: ACCOUNT_ID, cachedSettingsExpiryTime: 600000 }; // 10 minutes
vwoClient = await init(options);

Event Batching Configuration

The VWO SDK supports storing impression events while the device is offline, ensuring no data loss. These events are batched and seamlessly synchronized with VWO servers once the device reconnects to the internet. Additionally, online event batching allows synchronization of impression events while the device is online. This feature can be configured by setting either the minimum batch size or the batch upload time interval during SDK initialization.

NOTE: The batching will trigger based on whichever condition is met first if using both options.

Parameter	Description	Required	Type	Example
batchMinSize	Minimum size of the batch to upload.	No	number	10
batchUploadTimeInterval	Batch upload time interval in milliseconds. Please specify at least a few minutes.	No	number	300000

Example usage:

const options: VWOInitOptions = { sdkKey: SDK_KEY, accountId: ACCOUNT_ID, batchMinSize: 10, batchUploadTimeInterval: 300000 }; // 5 minutes
vwoClient = await init(options);

Authors

• Vishwajeet Singh

Changelog

Refer CHANGELOG.md

Contributing

Please go through our contributing guidelines

Code of Conduct

Code of Conduct

License

Apache License, Version 2.0

Copyright 2024-2025 Wingify Software Pvt. Ltd.