> ## Documentation Index
> Fetch the complete documentation index at: https://docs.mixpanel.com/llms.txt
> Use this file to discover all available pages before exploring further.

# OpenFeature Provider (Java)

## Overview

This guide covers using Mixpanel's [Feature Flags](/docs/featureflags) through the [OpenFeature](https://openfeature.dev/) standard with the Mixpanel Java 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 (Java)](/docs/tracking-methods/sdks/java/java-flags) guide.

## Prerequisites

* Enterprise subscription plan with Feature Flags enabled
* Java 8 or higher
* Project Token from your [Mixpanel Project Settings](/docs/orgs-and-projects/managing-projects#find-your-project-tokens)

## Installation

### Maven

```xml theme={"system"}
<dependency>
    <groupId>com.mixpanel</groupId>
    <artifactId>mixpanel-java-openfeature</artifactId>
    <version>0.1.0</version>
</dependency>
<dependency>
    <groupId>dev.openfeature</groupId>
    <artifactId>sdk</artifactId>
    <version>1.20.1</version>
</dependency>
```

### Gradle

```groovy theme={"system"}
implementation 'com.mixpanel:mixpanel-java-openfeature:0.1.0'
implementation 'dev.openfeature:sdk:1.20.1'
```

## Quick Start

```java theme={"system"}
import com.mixpanel.openfeature.MixpanelProvider;
import com.mixpanel.mixpanelapi.featureflags.config.LocalFlagsConfig;
import dev.openfeature.sdk.OpenFeatureAPI;
import dev.openfeature.sdk.Client;

// 1. Create and register the provider with local evaluation
MixpanelProvider provider = new MixpanelProvider(
    "YOUR_PROJECT_TOKEN",
    new LocalFlagsConfig("YOUR_PROJECT_TOKEN")
);
OpenFeatureAPI api = OpenFeatureAPI.getInstance();
api.setProvider(provider);

// 2. Get a client and evaluate flags
Client client = api.getClient();
boolean showNewFeature = client.getBooleanValue("new-feature-flag", false);

if (showNewFeature) {
    System.out.println("New feature is enabled!");
}
```

## Initialization

### Local Evaluation (Recommended)

<Warning>
  Targeting by Mixpanel cohorts and sticky variants are not supported in Local Evaluation mode.
</Warning>

```java theme={"system"}
MixpanelProvider provider = new MixpanelProvider(
    "YOUR_PROJECT_TOKEN",
    new LocalFlagsConfig("YOUR_PROJECT_TOKEN")
);
```

### Remote Evaluation

```java theme={"system"}
MixpanelProvider provider = new MixpanelProvider(
    "YOUR_PROJECT_TOKEN",
    new RemoteFlagsConfig("YOUR_PROJECT_TOKEN")
);
```

### Using an Existing MixpanelAPI Instance

```java theme={"system"}
MixpanelAPI mixpanel = new MixpanelAPI(new LocalFlagsConfig("YOUR_PROJECT_TOKEN"));
LocalFlagsProvider localFlags = mixpanel.getLocalFlags();
localFlags.startPollingForDefinitions();

MixpanelProvider 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()`, `getIntegerValue()`, `getDoubleValue()`, or `getObjectValue()` |
| Dynamic Config     | JSON object                             | `getObjectValue()`                                                                                      |

```java theme={"system"}
Client client = api.getClient();

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

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

// Experiment with numeric variants
int maxItems = client.getIntegerValue("max-items", 10);
double threshold = client.getDoubleValue("score-threshold", 0.5);

// Dynamic Config
Value featureConfig = client.getObjectValue("homepage-layout", new Value("default"));
```

### Evaluation Context

```java theme={"system"}
MutableContext context = new MutableContext();
context.setTargetingKey("user-123");
context.add("email", "user@example.com");
context.add("plan", "premium");
context.add("beta_tester", true);

boolean value = client.getBooleanValue("premium-feature", false, context);
```

<Note>
  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.
</Note>

### Full Resolution Details

```java theme={"system"}
FlagEvaluationDetails<Boolean> details = client.getBooleanDetails("my-feature", false);

System.out.println(details.getValue());
System.out.println(details.getVariant());
System.out.println(details.getReason());
System.out.println(details.getErrorCode());
```

### Accessing the Underlying MixpanelAPI

```java theme={"system"}
MixpanelAPI mixpanel = provider.getMixpanel();
```

### Shutdown

```java theme={"system"}
provider.shutdown();
```

## 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

1. **Provider not ready:** Flag definitions are polled asynchronously. Allow time for the initial fetch.
2. **Invalid project token:** Verify the token matches your Mixpanel project.
3. **Flag not configured:** Verify the flag exists and is enabled.

### Type Mismatch Errors

1. Verify the flag's value type matches your evaluation method.
2. Use `getObjectValue()` for JSON objects.
3. Integer evaluation accepts `Long` and whole-number `Double` values within `Integer` bounds. Double evaluation accepts any numeric type.