LaunchDarkly Feature Flags

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Why

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Setup

1. Add tooling-feature-flags-launch-darkly to apps/backend/package.json.
2. Run make deps-install.
3. Configure the environment:

featureFlags: {
  client: FeatureFlagClientType.LAUNCH_DARKLY,
  cacheMs: 30_000,
  sdkKey: process.env.LAUNCHDARKLY_SDK_KEY,
  exposedFlags: ['new-dashboard'],
},

4. Set LAUNCHDARKLY_SDK_KEY in the deployment environment.

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Evaluation context

• userId → context key (defaults to anonymous)
• organizationId, environment, and attributes → context attributes

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Gotchas

• The SDK initializes during buildFeatureFlags() — allow a few seconds on cold start.
• String flag values surface as variant with enabled: true.
• Use cacheMs to reduce SDK chatter; request caching still applies per HTTP request.

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What’s next?

• Feature flags overview
• PostHog provider
• Configuration system