OpenFeature Providers

OpenFeature is a CNCF-incubating open standard for feature flagging. GrowthBook provides OpenFeature provider SDKs for Python, Go, .NET, and Java — listed in the OpenFeature ecosystem.

Prerequisites

The API host:

Environment	API Host
Cloud	`https://cdn.growthbook.io`
Self-hosted	Your own GrowthBook URL (e.g. `https://growthbook.example.com`)

Why Use OpenFeature with GrowthBook?

OpenFeature defines a vendor-neutral interface for evaluating feature flags. Using a GrowthBook OpenFeature provider means:

Vendor portability — Your flag evaluation code is identical regardless of which provider is active. Switching from or to GrowthBook only requires changing the provider bootstrap, not a single flag call.
Standardized API — Teams use the same OpenFeature interface they already know across all services.
Ecosystem compatibility — OpenFeature-aware tooling — including OpenTelemetry hooks and other instrumentation — works automatically with GrowthBook.
Polyglot consistency — The same conceptual API spans Python, Go, .NET, Java (and more), giving teams a single mental model.

When to use the native GrowthBook SDK insteadThe native GrowthBook SDKs expose features that go beyond the OpenFeature interface: Sticky Bucketing, Visual Editor experiments, inline experiment definitions, and real-time SSE streaming. If you need those capabilities, use the native SDK for your language instead.

Installation & Setup

Python
Go
.NET
Java

GitHub: growthbook-openfeature-provider-python | PyPI: growthbook-openfeature-providerRequirements: Python 3.9+

pip install growthbook-openfeature-provider

Async setup (recommended for async frameworks like FastAPI, aiohttp):

import asyncio
from openfeature.api import OpenFeatureAPI
from openfeature.evaluation_context import EvaluationContext
from growthbook_openfeature_provider import GrowthBookProvider, GrowthBookProviderOptions

async def main():
    provider = GrowthBookProvider(GrowthBookProviderOptions(
        api_host="https://cdn.growthbook.io",
        client_key="sdk-abc123"
    ))
    await provider.initialize()
    OpenFeatureAPI.set_provider(provider)

    client = OpenFeatureAPI.get_client("my-app")
    # ... evaluate flags ...

    await provider.close()

asyncio.run(main())

Synchronous setup:

from openfeature.api import OpenFeatureAPI
from growthbook_openfeature_provider import GrowthBookProvider, GrowthBookProviderOptions

provider = GrowthBookProvider(GrowthBookProviderOptions(
    api_host="https://cdn.growthbook.io",
    client_key="sdk-abc123"
))
provider.initialize_sync()
OpenFeatureAPI.set_provider(provider)

client = OpenFeatureAPI.get_client("my-app")

GitHub: growthbook-openfeature-provider-go

go get github.com/growthbook/growthbook-openfeature-provider-go

package main

import (
    "context"
    growthbook "github.com/growthbook/growthbook-openfeature-provider-go"
    "github.com/open-feature/go-sdk/openfeature"
)

func main() {
    provider := growthbook.NewProvider(
        growthbook.WithAPIHost("https://cdn.growthbook.io"),
        growthbook.WithClientKey("sdk-abc123"),
    )

    openfeature.SetProvider(provider)
    client := openfeature.NewClient("my-app")

    // ... evaluate flags ...
}

GitHub: growthbook-openfeature-provider-dotnet

dotnet add package GrowthBook.OpenFeature

using OpenFeature;
using GrowthBook.OpenFeature;

var provider = new GrowthBookProvider(new GrowthBookProviderOptions
{
    ApiHost = "https://cdn.growthbook.io",
    ClientKey = "sdk-abc123"
});

await Api.Instance.SetProviderAsync(provider);
var client = Api.Instance.GetClient("my-app");

// ... evaluate flags ...

GitHub: growthbook-openfeature-provider-java

<dependency>
    <groupId>io.growthbook</groupId>
    <artifactId>growthbook-openfeature-provider</artifactId>
    <version>1.0.0</version>
</dependency>

import dev.openfeature.sdk.OpenFeatureAPI;
import io.growthbook.openfeature.GrowthBookProvider;

GrowthBookProvider provider = GrowthBookProvider.builder()
    .apiHost("https://cdn.growthbook.io")
    .clientKey("sdk-abc123")
    .build();

OpenFeatureAPI.getInstance().setProvider(provider);
Client client = OpenFeatureAPI.getInstance().getClient("my-app");

// ... evaluate flags ...

Evaluation Context (Targeting Attributes)

Pass user attributes to the OpenFeature client via an EvaluationContext. These become GrowthBook targeting attributes used for percentage rollouts, feature targeting rules, and experiment bucketing. The targetingKey maps to the user ID in GrowthBook. Additional attributes (e.g. country, plan, email) are matched against your feature flag targeting conditions.

Python
Go
.NET
Java

from openfeature.evaluation_context import EvaluationContext

context = EvaluationContext(
    targeting_key="user-123",
    attributes={
        "country": "US",
        "plan": "premium",
        "email": "user@example.com",
    }
)

context := openfeature.NewEvaluationContext(
    "user-123",
    map[string]interface{}{
        "country": "US",
        "plan":    "premium",
        "email":   "user@example.com",
    },
)

var context = EvaluationContext.Builder()
    .SetTargetingKey("user-123")
    .Set("country", "US")
    .Set("plan", "premium")
    .Set("email", "user@example.com")
    .Build();

EvaluationContext context = new ImmutableContext("user-123", Map.of(
    "country", new Value("US"),
    "plan", new Value("premium"),
    "email", new Value("user@example.com")
));

Evaluating Feature Flags

OpenFeature defines five value types. GrowthBook’s feature flags map to all of them.

Boolean

The most common type — use for on/off feature gates.

Python
Go
.NET
Java

# Synchronous
enabled = client.get_boolean_value("dark-mode", False, context)

# Async (returns FlagEvaluationDetails with value, reason, variant, etc.)
details = await provider.resolve_boolean_details_async("dark-mode", False, context)
enabled = details.value

enabled, _ := client.BooleanValue(context, "dark-mode", false, openfeature.EvaluationContext{})

var enabled = await client.GetBooleanValueAsync("dark-mode", false, context);

Boolean enabled = client.getBooleanValue("dark-mode", false, context);

String

Use for multi-variant flags where the value is a string (e.g. button color, layout variant).

Python
Go
.NET
Java

variant = client.get_string_value("button-color", "blue", context)

variant, _ := client.StringValue(context, "button-color", "blue", openfeature.EvaluationContext{})

var variant = await client.GetStringValueAsync("button-color", "blue", context);

String variant = client.getStringValue("button-color", "blue", context);

Integer & Float/Double

Use for numeric feature values such as rate limits, timeouts, or pricing.

Python
Go
.NET
Java

request_limit = client.get_integer_value("api-request-limit", 100, context)
price = client.get_float_value("subscription-price", 9.99, context)

requestLimit, _ := client.IntValue(context, "api-request-limit", 100, openfeature.EvaluationContext{})
price, _ := client.FloatValue(context, "subscription-price", 9.99, openfeature.EvaluationContext{})

var requestLimit = await client.GetIntegerValueAsync("api-request-limit", 100, context);
var price = await client.GetDoubleValueAsync("subscription-price", 9.99, context);

Integer requestLimit = client.getIntegerValue("api-request-limit", 100, context);
Double price = client.getDoubleValue("subscription-price", 9.99, context);

Object

Use for structured feature values (e.g. configuration payloads, theme objects).

Python
Go
.NET
Java

config = client.get_object_value("theme-config", {"color": "blue"}, context)

config, _ := client.ObjectValue(context, "theme-config", map[string]interface{}{"color": "blue"}, openfeature.EvaluationContext{})

var config = await client.GetObjectValueAsync("theme-config", new Value(new Structure(new Dictionary<string, Value> { { "color", new Value("blue") } })), context);

Value config = client.getObjectValue("theme-config", new Value(Map.of("color", new Value("blue"))), context);

Configuration Options

Option	Python	Go	.NET	Java	Description
`api_host`/`apiHost`	✓	✓	✓	✓	GrowthBook CDN or self-hosted URL
`client_key`/`clientKey`	✓	✓	✓	✓	SDK Connection key from GrowthBook
`decryption_key`	✓	—	—	—	Key for encrypted SDK endpoint payloads
`cache_ttl`	✓	✓	—	—	Seconds before re-fetching features (default: 60)
`enabled`	✓	—	✓	—	Enable/disable the provider entirely
`qa_mode`	✓	—	—	—	Forces all experiments into the control variation

Shutdown & Cleanup

Always shut down the provider when your application exits to close background connections.

Python
Go
.NET
Java

await provider.close()       # async
# or
provider.close_sync()        # sync

provider.Shutdown()

await Api.Instance.ShutdownAsync();

OpenFeatureAPI.getInstance().shutdown();

Client

Server

Prerequisites

Why Use OpenFeature with GrowthBook?

Installation & Setup

Evaluation Context (Targeting Attributes)

Evaluating Feature Flags

Boolean

String

Integer & Float/Double

Object

Configuration Options

Shutdown & Cleanup

Further Reading

Client

Server

Documentation Index

​Prerequisites

​Why Use OpenFeature with GrowthBook?

​Installation & Setup

​Evaluation Context (Targeting Attributes)

​Evaluating Feature Flags

​Boolean

​String

​Integer & Float/Double

​Object

​Configuration Options

​Shutdown & Cleanup

​Further Reading

Prerequisites

Why Use OpenFeature with GrowthBook?

Installation & Setup

Evaluation Context (Targeting Attributes)

Evaluating Feature Flags

Boolean

String

Integer & Float/Double

Object

Configuration Options

Shutdown & Cleanup

Further Reading