OpenFeature Provider (Web)

Overview

This guide covers using Mixpanel’s Feature Flags through the OpenFeature standard with the Mixpanel Web OpenFeature provider. OpenFeature provides a vendor-agnostic API for feature flag evaluation, allowing you to switch between providers without changing your application code. For the native Mixpanel SDK approach, see the Feature Flags (Web) guide.

Prerequisites

Enterprise subscription plan with Feature Flags enabled
Project Token from your Mixpanel Project Settings

Installation

npm install @mixpanel/openfeature-web-provider @openfeature/web-sdk mixpanel-browser

Quick Start

import mixpanel from 'mixpanel-browser';
import { OpenFeature } from '@openfeature/web-sdk';
import { MixpanelProvider } from '@mixpanel/openfeature-web-provider';

// 1. Initialize Mixpanel with feature flags
mixpanel.init('YOUR_PROJECT_TOKEN', {
  flags: {
    context: { plan: 'premium' }
  }
});

// 2. Create and register the Mixpanel provider
const provider = new MixpanelProvider(mixpanel.flags);
await OpenFeature.setProviderAndWait(provider);

// 3. Get a client and evaluate flags
const client = OpenFeature.getClient();
const showNewFeature = client.getBooleanValue('new-feature-flag', false);

if (showNewFeature) {
  console.log('New feature is enabled!');
}

Usage

Flag Types and Evaluation Methods

Mixpanel Flag Type	Variant Values	OpenFeature Method
Feature Gate	`true` / `false`	`getBooleanValue()`
Experiment	boolean, string, number, or JSON object	`getBooleanValue()`, `getStringValue()`, `getNumberValue()`, or `getObjectValue()`
Dynamic Config	JSON object	`getObjectValue()`

const client = OpenFeature.getClient();

// Feature Gate
const isFeatureOn = client.getBooleanValue('new-checkout', false);

// Experiment with string variants
const buttonColor = client.getStringValue('button-color-test', 'blue');

// Experiment with number variants
const maxItems = client.getNumberValue('max-items', 10);

// Dynamic Config
const featureConfig = client.getObjectValue('homepage-layout', {
  layout: 'grid',
  itemsPerRow: 3
});

Evaluation Context

Context must be set globally via OpenFeature.setContext():

await OpenFeature.setContext({
  email: 'user@example.com',
  plan: 'premium'
});

Per-evaluation context (the optional third argument to evaluation methods) is not supported by this provider. Context must be set globally via OpenFeature.setContext(), which triggers a re-fetch of flag values from Mixpanel.

Runtime Properties

Pass custom_properties in the evaluation context for runtime targeting:

await OpenFeature.setContext({
  custom_properties: {
    tier: 'enterprise',
    seats: 50,
    industry: 'technology'
  }
});

Unlike some providers, targetingKey is not used as a special bucketing key. It is passed as another context property. Mixpanel’s server-side configuration determines which properties are used for targeting and bucketing.

Full Resolution Details

const details = client.getBooleanDetails('my-feature', false);

console.log(details.value);
console.log(details.variant);
console.log(details.reason);
console.log(details.errorCode);

React Integration

import { OpenFeatureProvider, useBooleanFlagValue } from '@openfeature/react-sdk';
import { OpenFeature } from '@openfeature/web-sdk';
import mixpanel from 'mixpanel-browser';
import { MixpanelProvider } from '@mixpanel/openfeature-web-provider';

// Initialize outside of component
mixpanel.init('YOUR_PROJECT_TOKEN', {
  flags: {
    context: { plan: 'premium' }
  }
});
const provider = new MixpanelProvider(mixpanel.flags);
OpenFeature.setProvider(provider);

function App() {
  return (
    <OpenFeatureProvider>
      <MyComponent />
    </OpenFeatureProvider>
  );
}

function MyComponent() {
  const showBanner = useBooleanFlagValue('show-banner', false);

  return (
    <div>
      {showBanner && <Banner message="Welcome to our new feature!" />}
    </div>
  );
}

User Identity

This provider does not call mixpanel.identify(). Manage identity through Mixpanel directly:

mixpanel.identify('user-123');

Error Handling

Error Code	When
`PROVIDER_NOT_READY`	Flags evaluated before the provider has finished initializing
`FLAG_NOT_FOUND`	The requested flag does not exist in Mixpanel
`TYPE_MISMATCH`	The flag value type does not match the requested type

To avoid PROVIDER_NOT_READY, use setProviderAndWait:

await OpenFeature.setProviderAndWait(provider);

Troubleshooting

Flags Always Return Default Values

Feature flags not enabled: Ensure Mixpanel was initialized with flags enabled:

mixpanel.init('YOUR_TOKEN', { flags: { context: { plan: 'premium' } } });

Provider not ready: Use setProviderAndWait to ensure initialization.
Network issues: Check the browser console for failed requests.
Flag not configured: Verify the flag exists and is enabled.

Flags Not Updating After Context Change

Update context and the provider will re-fetch flags:

await OpenFeature.setContext({ plan: 'premium' });

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OpenFeature Provider (Web)

Overview

Prerequisites

Installation

Quick Start

Usage

Flag Types and Evaluation Methods

Evaluation Context

Runtime Properties

Full Resolution Details

React Integration

User Identity

Error Handling

Troubleshooting

Flags Always Return Default Values

Flags Not Updating After Context Change

​Overview

​Prerequisites

​Installation

​Quick Start

​Usage

​Flag Types and Evaluation Methods

​Evaluation Context

​Runtime Properties

​Full Resolution Details

​React Integration

​User Identity

​Error Handling

​Troubleshooting

​Flags Always Return Default Values

​Flags Not Updating After Context Change

Overview

Prerequisites

Installation

Quick Start

Usage

Flag Types and Evaluation Methods

Evaluation Context

Runtime Properties

Full Resolution Details

React Integration

User Identity

Error Handling

Troubleshooting

Flags Always Return Default Values

Flags Not Updating After Context Change