> For the complete documentation index, see [llms.txt](https://developer.harness.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developer.harness.io/feature-management-experimentation/new-to-fme/sdks-and-customer-deployed-components/server-side-sdks.md). # Server-side SDKs ## Overview Harness FME provides server-side SDKs that let you evaluate feature flags, run experiments, and control rollouts from your backend services. These SDKs are designed for high-throughput, low-latency environments where feature logic must run securely and reliably without exposing rules or targeting logic to the client. By integrating a server-side SDK, you can: * Evaluate targeting rules securely on the server * Maintain consistent behavior across multiple environments * Implement feature rollouts without redeploying backend code * Collect event data for experiment analysis * Use a bucketing key to control percentage-based rollouts independently of the key used for targeting (for example, bucket by account ID while still targeting individual users) {% hint style="info" %} **MATCHING KEY VS. BUCKETING KEY** Every server-side SDK supports passing a compound key (a matching key plus a separate bucketing key). {% endhint %} ## Get started Select a backend language or framework to begin.
Elixir Thin Client SDKElixir Thin Client SDK
Go SDKGo SDK
Java SDKJava SDK
.NET SDK.NET SDK
NodeJS SDKNode.js SDK
PHP SDKPHP SDK
PHP Thin Client SDKPHP Thin Client SDK
Python SDKPython SDK
Ruby SDKRuby SDK
{% @harness-feedback/feedback %}