# LaunchDarkly Rust SDK Evaluation Engine

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## LaunchDarkly overview

[LaunchDarkly](https://www.launchdarkly.com) is a feature management platform that serves trillions of feature flags daily to help teams build better software, faster. [Get started](https://docs.launchdarkly.com/home/getting-started) using LaunchDarkly today!

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## Getting started

This repository contains the internal feature flag evaluation logic and data model used by the [LaunchDarkly Rust SDK](https://github.com/launchdarkly/rust-server-sdk). It is packaged separately because it is also used by internal LaunchDarkly components. Applications using the LaunchDarkly Rust SDK should not need to reference this package directly.

## Learn more

Read our [documentation](http://docs.launchdarkly.com) for in-depth instructions on configuring and using LaunchDarkly. You can also head straight to the [complete reference guide for the Rust SDK](https://docs.launchdarkly.com/sdk/server-side/rust), or the [generated API documentation](https://docs.rs/launchdarkly-server-sdk-evaluation) for this project.

## Minimum Supported Rust Version

This project aims to maintain compatibility with a Rust version that is at least six months old.

Version updates may occur more frequently than the policy guideline states if external forces require it. For example, a CVE in a downstream dependency requiring an MSRV bump would be considered an acceptable reason to violate the six month guideline.

## Contributing

We encourage pull requests and other contributions from the community. Check out our [contributing guidelines](CONTRIBUTING.md) for instructions on how to contribute to this SDK.

## About LaunchDarkly

* LaunchDarkly is a continuous delivery platform that provides feature flags as a service and allows developers to iterate quickly and safely. We allow you to easily flag your features and manage them from the LaunchDarkly dashboard.  With LaunchDarkly, you can:
    * Roll out a new feature to a subset of your users (like a group of users who opt-in to a beta tester group), gathering feedback and bug reports from real-world use cases.
    * Gradually roll out a feature to an increasing percentage of users, and track the effect that the feature has on key metrics (for instance, how likely is a user to complete a purchase if they have feature A versus feature B?).
    * Turn off a feature that you realize is causing performance problems in production, without needing to re-deploy, or even restart the application with a changed configuration file.
    * Grant access to certain features based on user attributes, like payment plan (eg: users on the ‘gold’ plan get access to more features than users in the ‘silver’ plan). Disable parts of your application to facilitate maintenance, without taking everything offline.
* LaunchDarkly provides feature flag SDKs for a wide variety of languages and technologies. Read [our documentation](https://docs.launchdarkly.com/docs) for a complete list.
* Explore LaunchDarkly
    * [launchdarkly.com](https://www.launchdarkly.com/ "LaunchDarkly Main Website") for more information
    * [docs.launchdarkly.com](https://docs.launchdarkly.com/  "LaunchDarkly Documentation") for our documentation and SDK reference guides
    * [apidocs.launchdarkly.com](https://apidocs.launchdarkly.com/  "LaunchDarkly API Documentation") for our API documentation
    * [launchdarkly.com/blog](https://launchdarkly.com/blog/  "LaunchDarkly Blog Documentation") for the latest product updates