SDKs Overview

Flipswitch provides two integration paths: official SDKs with real-time SSE streaming, or any OpenFeature OFREP provider for polling-based evaluation.

Official SDKs

JavaScript

React, Node.js, browser

Java

Spring Boot, server-side

Python

FastAPI, Django, server-side

Go

Gin, net/http, server-side

Open source on GitHub: JavaScript | Java | Python | Go

OpenFeature / OFREP

Flipswitch implements the OpenFeature Remote Evaluation Protocol (OFREP), so any language with an OpenFeature SDK and OFREP provider can evaluate flags without a dedicated Flipswitch SDK.

OFREP providers use polling to fetch flag values. For instant updates via SSE, use an official SDK above.

.NET

ASP.NET, server-side

Rust

Tokio, server-side

Swift

iOS, macOS

PHP

Laravel, server-side

Ruby

Rails, server-side

See Other Languages (OFREP) for setup instructions.

Feature Comparison

Feature	Official SDKs	OFREP
Flag evaluation	✓	✓
Real-time updates (SSE)	✓	✗
Automatic reconnection	✓	✗
Polling fallback	✓	✗
Local caching	✓	~
Event handlers	✓	✗
OpenFeature compatible	✓	✓

Official SDKs maintain a persistent SSE connection for millisecond-latency updates. OFREP providers poll at a configurable interval, which is simpler but means flag changes aren't instant.

Configuration

All official SDKs share common options:

Option	Default	Description
`apiKey`	required	Your environment API key
`baseUrl`	`https://api.flipswitch.io`	Flipswitch server URL
`enableRealtime`	`true`	Enable SSE for instant updates
`enablePollingFallback`	`true`	Fall back to polling when SSE fails
`pollingInterval`	`30s`	Polling interval in fallback mode
`maxSseRetries`	`5`	Max SSE retries before polling fallback

Evaluation Context

Pass user attributes for targeting:

const context = {
  targetingKey: 'user-123',      // Required: unique identifier
  email: 'user@example.com',     // Custom attributes
  plan: 'premium',
  country: 'SE'
};

const value = await client.getBooleanValue('feature', false, context);

The targetingKey is required for consistent gradual rollouts.