Other Languages (OFREP)

Flipswitch natively implements the OpenFeature Remote Evaluation Protocol (OFREP), so any language with an OpenFeature SDK and OFREP provider works directly — no custom integration needed.

Browse the full OpenFeature ecosystem for available SDKs and providers.

OFREP providers use polling for flag updates. For real-time SSE streaming, use an official Flipswitch SDK where available.

.NET

GitHub: open-feature/dotnet-sdk · open-feature/dotnet-sdk-contrib

dotnet add package OpenFeature.Providers.Ofrep

using OpenFeature;
using OpenFeature.Contrib.Providers.Ofrep;

var provider = new OFREPProvider(new OFREPProviderOptions
{
    BaseUrl = "https://api.flipswitch.io",
    Headers = new Dictionary<string, string>
    {
        ["X-API-Key"] = "YOUR_API_KEY"
    }
});

await Api.Instance.SetProviderAsync(provider);
var client = Api.Instance.GetClient();

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

Rust

GitHub: open-feature/rust-sdk · open-feature/rust-sdk-contrib

cargo add open-feature open-feature-ofrep

use open_feature::{OpenFeature, EvaluationContext};
use open_feature_ofrep::OFREPProvider;

let provider = OFREPProvider::new(
    "https://api.flipswitch.io",
    Some("YOUR_API_KEY"),
);

let mut api = OpenFeature::singleton_mut().await;
api.set_provider(provider).await;

let client = api.create_client();
let dark_mode = client.get_bool_value("dark-mode", Some(&context), None).await?;

Swift

GitHub: open-feature/swift-sdk · open-feature/ofrep-swift-client-provider

Add via Swift Package Manager:

https://github.com/open-feature/ofrep-swift-client-provider.git

import OpenFeature
import OFREPProvider

let provider = OFREPProvider(
    baseURL: URL(string: "https://api.flipswitch.io")!,
    headers: ["X-API-Key": "YOUR_API_KEY"]
)

OpenFeatureAPI.shared.setProvider(provider: provider)
let client = OpenFeatureAPI.shared.getClient()

let darkMode = client.getBooleanValue(key: "dark-mode", defaultValue: false)

PHP

GitHub: open-feature/php-sdk · open-feature/php-sdk-contrib

composer require open-feature/sdk open-feature/ofrep-provider

use OpenFeature\OpenFeatureAPI;
use OpenFeature\Contrib\Providers\OFREP\OFREPProvider;

$provider = new OFREPProvider([
    'baseUrl' => 'https://api.flipswitch.io',
    'headers' => [
        'X-API-Key' => 'YOUR_API_KEY'
    ]
]);

$api = OpenFeatureAPI::getInstance();
$api->setProvider($provider);
$client = $api->getClient();

$darkMode = $client->getBooleanValue('dark-mode', false);

Ruby

GitHub: open-feature/ruby-sdk · open-feature/ruby-sdk-contrib

gem install openfeature-sdk

require 'openfeature/sdk'
require 'openfeature/contrib/providers/ofrep'

provider = OpenFeature::Contrib::Providers::OFREP.new(
  base_url: 'https://api.flipswitch.io',
  headers: { 'X-API-Key' => 'YOUR_API_KEY' }
)

OpenFeature::SDK.configure do |config|
  config.set_provider(provider)
end

client = OpenFeature::SDK.build_client
dark_mode = client.fetch_boolean_value(flag_key: 'dark-mode', default_value: false)

Direct OFREP API

You can also call the OFREP endpoints directly via HTTP — useful for scripting, testing, or languages without an OFREP provider yet.

Single Flag Evaluation

curl -X POST https://api.flipswitch.io/ofrep/v1/evaluate/flags/dark-mode \
  -H "X-API-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "context": {
      "targetingKey": "user-123",
      "email": "user@example.com"
    }
  }'

Response:

{
  "key": "dark-mode",
  "value": true,
  "variant": "enabled",
  "reason": "TARGETING_MATCH"
}

Bulk Evaluation

curl -X POST https://api.flipswitch.io/ofrep/v1/evaluate/flags \
  -H "X-API-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"context": {"targetingKey": "user-123"}}'

Response:

{
  "flags": [
    {"key": "dark-mode", "value": true, "variant": "enabled", "reason": "TARGETING_MATCH"},
    {"key": "max-items", "value": 50, "variant": "high", "reason": "DEFAULT"}
  ]
}

ETag Support

Use ETags for efficient caching:

# First request returns ETag header
curl -X POST https://api.flipswitch.io/ofrep/v1/evaluate/flags \
  -H "X-API-Key: YOUR_API_KEY" \
  -d '{"context": {"targetingKey": "user-123"}}'
# Response includes: ETag: "abc123"

# Subsequent requests with If-None-Match
curl -X POST https://api.flipswitch.io/ofrep/v1/evaluate/flags \
  -H "X-API-Key: YOUR_API_KEY" \
  -H 'If-None-Match: "abc123"' \
  -d '{"context": {"targetingKey": "user-123"}}'
# Returns 304 Not Modified if unchanged

All Supported Languages

Language	OpenFeature SDK	OFREP Provider
.NET	dotnet-sdk	dotnet-sdk-contrib
Rust	rust-sdk	rust-sdk-contrib
Swift	swift-sdk	ofrep-swift-client-provider
PHP	php-sdk	php-sdk-contrib
Ruby	ruby-sdk	ruby-sdk-contrib

For the latest SDKs and providers, see the OpenFeature ecosystem and the OFREP protocol spec.

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