OpenFeature Provider (Node.js)

Overview

This guide covers using Mixpanel’s Feature Flags through the OpenFeature standard with the Mixpanel Node.js 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 (Node.js) guide.

Prerequisites

Enterprise subscription plan with Feature Flags enabled
Node.js 10 or higher
Project Token from your Mixpanel Project Settings

Installation

npm install @mixpanel/openfeature-server-provider @openfeature/server-sdk mixpanel

Quick Start

import { OpenFeature } from "@openfeature/server-sdk";
import { MixpanelProvider } from "@mixpanel/openfeature-server-provider";
 
// 1. Create and register the provider with local evaluation
const provider = MixpanelProvider.createLocal("YOUR_PROJECT_TOKEN");
await OpenFeature.setProviderAndWait(provider);
 
// 2. Get a client and evaluate flags
const client = OpenFeature.getClient();
const showNewFeature = await client.getBooleanValue("new-feature-flag", false, {
  distinct_id: "user-123",
});
 
if (showNewFeature) {
  console.log("New feature is enabled!");
}

Initialization

Local Evaluation (Recommended)

⚠️

Targeting by Mixpanel cohorts and sticky variants are not supported in Local Evaluation mode.

const provider = MixpanelProvider.createLocal("YOUR_PROJECT_TOKEN");

Remote Evaluation

const provider = MixpanelProvider.createRemote("YOUR_PROJECT_TOKEN");

Using an Existing Mixpanel Instance

import Mixpanel from "mixpanel";
 
const mixpanel = Mixpanel.init("YOUR_PROJECT_TOKEN", {
  local_flags_config: {},
});
const localFlags = mixpanel.local_flags!;
localFlags.startPollingForDefinitions();
 
const provider = new MixpanelProvider(localFlags);

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();
const context = { distinct_id: "user-123" };
 
// Feature Gate
const isFeatureOn = await client.getBooleanValue("new-checkout", false, context);
 
// Experiment with string variants
const buttonColor = await client.getStringValue("button-color-test", "blue", context);
 
// Experiment with number variants
const maxItems = await client.getNumberValue("max-items", 10, context);
 
// Dynamic Config
const featureConfig = await client.getObjectValue("homepage-layout", {}, context);

Evaluation Context

// Global context
OpenFeature.setContext({ environment: "production" });
 
// Per-evaluation context (merged with and overrides global context)
const value = await client.getBooleanValue("premium-feature", false, {
  distinct_id: "user-123",
  email: "user@example.com",
  plan: "premium",
});

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 = await client.getBooleanDetails("my-feature", false, {
  distinct_id: "user-123",
});
 
console.log(details.value);
console.log(details.variant);
console.log(details.reason);
console.log(details.errorCode);

Accessing the Underlying Mixpanel Instance

const mixpanel = provider.mixpanel;
if (mixpanel) {
  mixpanel.track("button_clicked", { distinct_id: "user-123" });
}

Shutdown

await OpenFeature.close();

Error Handling

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

Troubleshooting

Flags Always Return Default Values

Provider not ready: Use setProviderAndWait() to ensure flags are ready before evaluation.
Invalid project token: Verify the token matches your Mixpanel project.
Flag not configured: Verify the flag exists and is enabled.

Type Mismatch Errors

Verify the flag’s value type matches your evaluation method. Use getObjectValue() for JSON objects.

Feature Flags (Node.js)Ruby

Was this page useful?