LaunchDarkly Developer Documentation

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LaunchDarkly provides feature flags as a service for Java · Python · Ruby · Go · Node.js · PHP · .NET. Control feature launches -- who sees what and when -- without multiple code deploys. Easy dashboard for phased rollouts, targeting and segmenting.
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Environments allow you to manage your feature flags throughout your entire development lifecycle — from local development to QA, staging, and production.

When you first sign up, you're provided with two environments within a project. By default, they're named Test and Production. Each environment has its own private SDK key, which is used to connect a LaunchDarkly SDK to a specific environment.

Each feature flag that you create has its own unique set of targeting rules for each environment. This means that you can change your flag rollout rules in a development or staging environment for QA testing before rolling out to production.

The LaunchDarkly sidebar has a dropdown widget that shows you the current project and environment and allows you to quickly switch environments.

You can manage your environments from your Account settings page. Here, you can add new environments to a project (for example, to give each developer on your team their own environment for local testing).

Each environment also has its own swatch color. The swatch color gives you a quick visual indication of which environment you're working on.

Each environment also has a time-to-live (TTL) setting. This sets the number of minutes that the PHP SDK can cache feature flag rules locally.

TTL settings

The TTL is only used in our PHP SDK, since PHP's shared-nothing architecture makes our streaming model impossible.

For customers using PHP, we recommend setting your TTL to 2 minutes in production environments. This lets our SDKs cache feature flag rules for 2 minutes, so most calls to variation will not make a remote request. The tradeoff is that changes you make to your feature flag rules on your dashboard will not take effect for 2 minutes.

If your site has relatively low traffic (fewer than one request per minute), you may wish to increase the TTL to 5 minutes or more to take better advantage of the local cache.

If the TTL is set to 0 minutes, the SDK will not use a local cache, and every call to variation will make a remote request to our CDN. You can set your TTL to 0 in testing environments to see changes reflected immediately, but we do not recommend a 0 minute TTL in production.