SDK Recipes
Use this reference to match a detected tech stack to the correct LaunchDarkly SDK.
Field | Value tables in this file are the index layer: package name, what to look for in the repo (detect files/patterns), a one-line install hint, and the official Docs link. Use them first to choose the right SDK and command—before opening a detail file.
Each recipe links to an SDK detail file under snippets/. Open that file for curated links to official docs, samples, and package registries. Ten of those files also include a copy-paste onboarding sample; the rest are pointer-only—follow LaunchDarkly's docs for install and initialization. Never commit real keys. Treat each Docs link in the table as canonical for API details and migrations.
Source of truth: Official LaunchDarkly SDK documentation is authoritative. Prefer each recipe's Docs link over summaries here.
Top 10 SDKs (start here)
These are the most common stacks—check here first before scanning less common SDKs below.
React (Web)
| Field | Value |
|---|---|
| Package | launchdarkly-react-client-sdk |
| Detect files | package.json |
| Detect patterns | react, react-dom, "react": |
| Install | npm install launchdarkly-react-client-sdk |
| Flag key behavior | camelCase by default. useFlags() transforms my-flag-key → myFlagKey. Disable with reactOptions: { useCamelCaseFlagKeys: false } on the provider. When wiring first-flag code, use the camelCased form unless the project disables it. |
| Docs | React SDK reference · React Web SDK reference |
SDK detail: snippets/react-web-sdk.md (includes onboarding sample)
API: Prefer asyncWithLDProvider with timeout (seconds; recommend 1–5) so the app renders after the JS client initializes; alternatively withLDProvider if you initialize after mount. See Initialize the client.
Next.js: If next is present, this client recipe covers browser/client-component flows; server routes and Server Components usually also need Node.js (Server) and an SDK key there—see the Next.js note under that recipe and Generate integration plan.
JavaScript (Browser)
| Field | Value |
|---|---|
| Package | @launchdarkly/js-client-sdk |
| Detect files | package.json, index.html |
| Detect patterns | webpack, vite, parcel, rollup; use when not using React / Vue wrappers |
| Install | npm install @launchdarkly/js-client-sdk |
| Docs | JavaScript SDK reference |
SDK detail: snippets/javascript-browser-sdk.md (includes onboarding sample)
API vs. other SDKs: The current browser package is @launchdarkly/js-client-sdk: createClient, start(), then waitForInitialization({ timeout }) (check result.status). See the browser SDK API docs. The legacy npm name launchdarkly-js-client-sdk (v3) used initialize() without start()—do not mix that flow with v4.
Node.js (Server)
| Field | Value |
|---|---|
| Package | @launchdarkly/node-server-sdk |
| Detect files | package.json |
| Detect patterns | express, fastify, koa, hapi, nestjs, next (API routes), "type": "module" |
| Install | npm install @launchdarkly/node-server-sdk |
| Docs | Node.js SDK reference (server-side) |
SDK detail: snippets/node-server-sdk.md (includes onboarding sample)
Next.js: next in Detect patterns only signals that the server-side Node SDK may apply (API routes / Route Handlers, Server Components, server-only code). Client components in the browser still need the React (Web) recipe (launchdarkly-react-client-sdk and a client-side ID)—do not silently pick only the Node server SDK for a full-stack Next app. Plan one or both SDKs depending on where flags are evaluated; align with Generate integration plan (Next.js callout there).
Python (Server)
| Field | Value |
|---|---|
| Package | launchdarkly-server-sdk (PyPI) |
| Detect files | requirements.txt, pyproject.toml, setup.py, Pipfile |
| Detect patterns | flask, django, fastapi, starlette |
| Install | pip install launchdarkly-server-sdk — optional: pip install launchdarkly-observability (requires SDK 9.12+; see Install the SDK) |
| Docs | Python SDK reference |
SDK detail: snippets/python-server-sdk.md (includes onboarding sample)
API: ldclient.set_config(Config(sdk_key)) then client = ldclient.get() (singleton). Optional plugins=[ObservabilityPlugin()] on Config with launchdarkly-observability. Forked workers: postfork(). See Initialize the client.
React Native
| Field | Value |
|---|---|
| Package | @launchdarkly/react-native-client-sdk |
| Detect files | package.json |
| Detect patterns | react-native |
| Install | npm install @launchdarkly/react-native-client-sdk |
| Flag key behavior | camelCase by default. Same behavior as React Web: useFlags() transforms my-flag-key → myFlagKey. Disable with reactOptions: { useCamelCaseFlagKeys: false }. |
| Docs | React Native SDK reference |
SDK detail: snippets/react-native-sdk.md (includes onboarding sample)
API: @launchdarkly/react-native-client-sdk v10 — ReactNativeLDClient (mobile key) + LDProvider + identify(context) on mount. Non-Expo: add @react-native-async-storage/async-storage and npx pod-install. See React Native SDK reference.
.NET (Server)
| Field | Value |
|---|---|
| Package | LaunchDarkly.ServerSdk (NuGet) |
| Detect files | *.csproj, *.sln, *.fsproj (look for BlazorWebAssembly, blazorwasm, UseBlazorWebAssembly, blazorserver, or Microsoft.AspNetCore.Components / Blazor in the project) |
| Detect patterns | Microsoft.AspNetCore, Microsoft.NET, Blazor, blazor, blazorserver (host/server UI—not WASM-only client projects) |
| Install | dotnet add package LaunchDarkly.ServerSdk — optional: dotnet add package LaunchDarkly.Observability (requires server SDK 8.10+; see Install the SDK) |
| Docs | .NET SDK reference (server-side) |
SDK detail: snippets/dotnet-server-sdk.md (includes onboarding sample)
API (current docs): LaunchDarkly.Sdk / LaunchDarkly.Sdk.Server — build config with Configuration.Builder(sdkKey).StartWaitTime(...).Build(), then new LdClient(config) before WebApplication.CreateBuilder → Build(). Prefer LdClient as a singleton in DI for real services. See Initialize the client.
Blazor: Blazor Server (and other server-hosted Blazor where .NET runs on the server) → this server-side SDK and an SDK key. Blazor WebAssembly runs in the browser → use .NET (Client) (LaunchDarkly.ClientSdk, Client-side ID). Inspect .csproj / SDK props: WASM projects typically use the Blazor WebAssembly workload or blazorwasm / UseBlazorWebAssembly; do not treat those as server-only.
Java (Server)
| Field | Value |
|---|---|
| Package | com.launchdarkly:launchdarkly-java-server-sdk (Maven Central) |
| Detect files | pom.xml, build.gradle, build.gradle.kts, *.kt (JVM services—see note below) |
| Detect patterns | spring, quarkus, micronaut, dropwizard, kotlin, ktor, org.jetbrains.kotlin |
| Install | Maven (pom.xml) and Gradle (Groovy / Kotlin DSL)—see Install (Maven and Gradle) below; pin version from SDK releases |
| Docs | Java SDK reference |
SDK detail: snippets/java-server-sdk.md (includes onboarding sample)
Install (Maven and Gradle): Install the SDK shows XML for Maven and Gradle coordinates. Match your build file (pom.xml, build.gradle, or build.gradle.kts). Example Gradle shortcut: implementation 'com.launchdarkly:launchdarkly-java-server-sdk:7.+' or implementation("com.launchdarkly:launchdarkly-java-server-sdk:7.+").
API: import com.launchdarkly.sdk.* / com.launchdarkly.sdk.server.* — new LDClient(sdkKey) (default startup wait), isInitialized(). See Initialize the client.
Kotlin (JVM) backends: For Ktor, Spring Boot + Kotlin, or other server-side Kotlin on the JVM, use this Java server SDK (launchdarkly-java-server-sdk) from Kotlin code—LaunchDarkly does not ship a separate Kotlin server artifact. build.gradle.kts plus .kt sources without Android-only signals should still match here. Android apps (Kotlin or Java) that talk to LaunchDarkly from the device use the Android client SDK recipe, not this server SDK.
Go (Server)
| Field | Value |
|---|---|
| Package | github.com/launchdarkly/go-server-sdk/v7 |
| Detect files | go.mod, go.sum |
| Detect patterns | net/http, gin, echo, fiber, chi |
| Install | go get github.com/launchdarkly/go-server-sdk/v7 |
| Docs | Go SDK reference |
SDK detail: snippets/go-server-sdk.md (includes onboarding sample)
Swift / iOS
| Field | Value |
|---|---|
| Package | LaunchDarkly (CocoaPods; SPM / Carthage via GitHub) |
| Detect files | Package.swift, Podfile, Cartfile, *.xcodeproj |
| Detect patterns | UIKit, SwiftUI, ios |
| Install | SPM, CocoaPods, or Carthage — see Install the SDK and ios-client-sdk.md; pin versions from SDK releases |
| Docs | iOS SDK reference · Set up iOS SDK (onboarding) |
SDK detail: snippets/ios-client-sdk.md (includes onboarding sample)
API: LDConfig(mobileKey:autoEnvAttributes:), LDContextBuilder, LDClient.start(…, startWaitSeconds:completion:) — see Initialize the client. Optional LaunchDarklyObservability (v9.14+).
Android
| Field | Value |
|---|---|
| Package | com.launchdarkly:launchdarkly-android-client-sdk |
| Detect files | build.gradle, build.gradle.kts, AndroidManifest.xml |
| Detect patterns | android, com.android, androidx |
| Install | See Install (two Gradle DSLs) below — same artifact, different syntax for Groovy vs Kotlin DSL |
| Docs | Android SDK reference |
Install (two Gradle DSLs): The Install the SDK topic shows both forms. Use the one that matches the app module file you have:
- Gradle Groovy (
build.gradle):implementation 'com.launchdarkly:launchdarkly-android-client-sdk:5.+' - Gradle Kotlin DSL (
build.gradle.kts):implementation("com.launchdarkly:launchdarkly-android-client-sdk:5.+")
SDK detail: snippets/android-client-sdk.md (includes onboarding sample)
Server-side SDKs (other)
Server-side SDKs use an SDK Key and are intended for backends where the key stays secret.
The five most-used server runtimes (Node.js, Python, .NET, Java, Go) are in Top 10 SDKs (start here) above.
Apex (Salesforce)
| Field | Value |
|---|---|
| Package | Deploy from apex-server-sdk (no NuGet/Maven module) |
| Detect files | sfdx-project.json, force-app, *.cls |
| Detect patterns | salesforce, Salesforce, Apex |
| Install | Follow the docs (SFDX deploy and LaunchDarkly Salesforce bridge) |
| Docs | Apex SDK reference |
SDK detail: snippets/apex-server-sdk.md
C++ (Server)
| Field | Value |
|---|---|
| Package | launchdarkly-cpp-server (via CMake FetchContent, vcpkg, or vendor) |
| Detect files | CMakeLists.txt, Makefile, *.cpp, *.h |
| Detect patterns | cmake, server-side C++ services |
| Install | See docs (CMake / vcpkg) |
| Docs | C++ SDK reference (server-side) |
SDK detail: snippets/cpp-server-sdk.md
Erlang / Elixir
| Field | Value |
|---|---|
| Package | Erlang: launchdarkly_server_sdk (Hex). Elixir: add the same dependency in mix.exs |
| Detect files | rebar.config, mix.exs |
| Detect patterns | erlang, elixir, phoenix |
| Install | Rebar or Mix per docs |
| Docs | Erlang SDK reference |
SDK detail: snippets/erlang-server-sdk.md
Haskell (Server)
| Field | Value |
|---|---|
| Package | launchdarkly-server-sdk (Cabal / Stack / Hackage) |
| Detect files | *.cabal, stack.yaml, package.yaml |
| Detect patterns | haskell, cabal, stack |
| Install | Add dependency per docs |
| Docs | Haskell SDK reference |
SDK detail: snippets/haskell-server-sdk.md
Lua (Server)
| Field | Value |
|---|---|
| Package | launchdarkly-server-sdk (LuaRocks) |
| Detect files | *.lua, *.rockspec |
| Detect patterns | lua, luarocks, OpenResty / NGINX / HAProxy Lua |
| Install | luarocks install launchdarkly-server-sdk (see docs for your runtime) |
| Docs | Lua SDK reference |
SDK detail: snippets/lua-server-sdk.md
PHP (Server)
| Field | Value |
|---|---|
| Package | launchdarkly/server-sdk |
| Detect files | composer.json |
| Detect patterns | laravel, symfony, slim |
| Install | composer require launchdarkly/server-sdk |
| Docs | PHP SDK reference |
SDK detail: snippets/php-server-sdk.md
Ruby (Server)
| Field | Value |
|---|---|
| Package | launchdarkly-server-sdk |
| Detect files | Gemfile, *.gemspec |
| Detect patterns | rails, sinatra, hanami |
| Install | gem install launchdarkly-server-sdk or add to Gemfile |
| Docs | Ruby SDK reference |
SDK detail: snippets/ruby-server-sdk.md
Rust (Server)
| Field | Value |
|---|---|
| Package | launchdarkly-server-sdk |
| Detect files | Cargo.toml |
| Detect patterns | actix, rocket, axum, warp |
| Install | cargo add launchdarkly-server-sdk |
| Docs | Rust SDK reference |
SDK detail: snippets/rust-server-sdk.md
Client-side SDKs (other)
Client-side SDKs use a Client-side ID for browser and desktop clients where that credential is expected to be visible in the app. Use the linked reference for bootstrap, privacy, and flag delivery behavior.
React (Web) and JavaScript (browser) are in Top 10 SDKs (start here) above.
Vue
| Field | Value |
|---|---|
| Package | launchdarkly-vue-client-sdk |
| Detect files | package.json |
| Detect patterns | vue, "vue": |
| Install | npm install launchdarkly-vue-client-sdk |
| Docs | Vue SDK reference |
SDK detail: snippets/vue-client-sdk.md
Angular, Svelte, Preact, and other browser frameworks
| Field | Value |
|---|---|
| Package | @launchdarkly/js-client-sdk |
| Detect files | package.json, angular.json, svelte.config.js |
| Detect patterns | @angular, svelte, preact |
| Install | npm install @launchdarkly/js-client-sdk |
| Docs | JavaScript SDK reference (no dedicated SDK; use the JS client) |
SDK detail: snippets/browser-frameworks-sdk.md
API: Same package and createClient / start() / waitForInitialization flow as JavaScript (Browser). Prefer javascript-browser-sdk.md for a copy-paste sample.
.NET (Client)
| Field | Value |
|---|---|
| Package | LaunchDarkly.ClientSdk |
| Detect files | *.csproj, *.sln (WASM: blazorwasm, BlazorWebAssembly, UseBlazorWebAssembly in project) |
| Detect patterns | Xamarin, MAUI, WPF, UWP, Avalonia, Blazor, blazor, blazorwasm |
| Install | dotnet add package LaunchDarkly.ClientSdk |
| Docs | .NET SDK reference (client-side) |
SDK detail: snippets/dotnet-client-sdk.md
Keys: MAUI, Xamarin, WPF, UWP (and similar native/desktop shells) use this package as LaunchDarkly’s .NET mobile client SDK with a mobile key. Blazor WebAssembly (browser-hosted UI) uses the same package with a Client-side ID. Blazor Server (and server-rendered interactive Blazor) → .NET (Server) with LaunchDarkly.ServerSdk. See Generate integration plan.
C++ (Client)
| Field | Value |
|---|---|
| Package | launchdarkly-cpp-client (CMake / vcpkg per docs) |
| Detect files | CMakeLists.txt, Makefile, *.cpp, *.h |
| Detect patterns | Desktop or embedded C++ clients |
| Install | See docs |
| Docs | C++ SDK reference (client-side) |
SDK detail: snippets/cpp-client-sdk.md
Electron
| Field | Value |
|---|---|
| Package | launchdarkly-electron-client-sdk |
| Detect files | package.json |
| Detect patterns | electron |
| Install | npm install launchdarkly-electron-client-sdk |
| Docs | Electron SDK reference |
SDK detail: snippets/electron-client-sdk.md
Node.js (Client)
| Field | Value |
|---|---|
| Package | launchdarkly-node-client-sdk |
| Detect files | package.json |
| Detect patterns | Node scripts or desktop tooling without Electron (see Electron above) |
| Install | npm install launchdarkly-node-client-sdk |
| Docs | Node.js SDK reference (client-side) |
SDK detail: snippets/node-client-sdk.md
Roku (BrightScript)
| Field | Value |
|---|---|
| Package | roku-client-sdk (GitHub releases) |
| Detect files | manifest, *.brs, SceneGraph *.xml |
| Detect patterns | brightscript, roku, SceneGraph |
| Install | Add SDK components per docs |
| Docs | Roku SDK reference |
SDK detail: snippets/roku-client-sdk.md
Mobile SDKs (other)
These entries are mobile or app-embedded targets. Most use a Mobile key; Flutter web is an exception (see below). Each Docs link points at the official reference (same pages as the client-side SDK family on launchdarkly.com/docs).
Swift / iOS, Android, and React Native are in Top 10 SDKs (start here) above.
Flutter
LaunchDarkly documents this as the Flutter client SDK (launchdarkly_flutter_client_sdk); it is listed here because iOS, Android, and typical desktop app builds use a Mobile key.
| Field | Value |
|---|---|
| Package | launchdarkly_flutter_client_sdk |
| Detect files | pubspec.yaml |
| Detect patterns | flutter |
| Install | flutter pub add launchdarkly_flutter_client_sdk |
| Docs | Flutter SDK reference |
SDK detail: snippets/flutter-client-sdk.md
Keys: Mobile key for iOS, Android, and typical desktop app targets; Client-side ID (and your bundler’s public env pattern) for Flutter web. Multi-target apps may need separate config per surface—see Generate integration plan.
Edge SDKs
Edge SDKs run on edge platforms and use an SDK Key (see each platform's reference for environment and constraints).
| Platform | Detect pattern | Docs |
|---|---|---|
| Akamai EdgeWorkers | bundle.json, edgeworkers |
Akamai SDK reference |
| Cloudflare Workers | wrangler.toml, @cloudflare/workers-types |
Cloudflare SDK reference |
| Fastly Compute | Fastly service config, @fastly/js-compute (per your stack) |
Fastly SDK reference |
| Vercel Edge | vercel.json with edge functions, @vercel/edge |
Vercel SDK reference |
SDK detail: snippets/edge-sdks.md (all edge platforms)