Get started with the flagd integrations

⭐ Community Toolkit

flagd is a feature flag evaluation engine that provides an OpenFeature-compliant backend for managing and evaluating feature flags in real-time. The Aspire flagd integration lets you model a flagd server as a first-class resource in your AppHost, then hand the connection information to any consuming app — regardless of language.

Why use flagd with Aspire

Adding flagd through Aspire — rather than wiring up containers and connection strings by hand — gives you:

• Zero-config local development. Aspire runs flagd from the ghcr.io/open-feature/flagd container image with no manual container management required.
• Consistent connection info across languages. Once you reference the flagd resource from a consuming app, Aspire injects connection properties as environment variables in a predictable format that works from C#, TypeScript, Python, Go, or any other language.
• Built-in health checks. The hosting integration automatically registers a health check against the flagd /healthz endpoint so the dashboard and your orchestrator can tell when the server is ready.
• Dashboard observability. The flagd resource shows up in the Aspire dashboard with logs and status alongside your other services.
• Multi-language OpenFeature clients. Any OpenFeature-compatible SDK with a flagd provider — C#, Go, Python, or TypeScript — works with the injected connection information.

How the pieces fit together

The flagd integration has two sides: a hosting integration that you use in your AppHost to model the flagd resource, and a connection story for consuming apps that reference it.

architecture-beta

  group apphost(server)[AppHost]
  group consumer(server)[Consuming app]

  service hosting(server)[Hosting integration] in apphost
  service flagd(server)[flagd server] in apphost

  service app(server)[App] in consumer

  hosting:R --> L:flagd
  flagd:R --> L:app

The hosting integration lives in your AppHost project and models the flagd server as a resource. Consuming apps reference it and use the connection information Aspire injects to evaluate feature flags via the OpenFeature SDK.

Getting there is a two-step process: model the flagd resource in your AppHost, then connect to it from each app that needs it.

1. Model flagd in your AppHost

   Add the flagd hosting integration to your AppHost, then declare a flagd resource and reference it from the apps that need feature flags. The flagd Hosting integration article walks through every capability — file-based flag sync, port customization, log levels, and health checks.

   Set up flagd in the AppHost

2. Connect from your consuming app

   When you reference a flagd resource from a consuming app, Aspire injects its connection information as environment variables. See Connect to flagd for the connection properties reference and per-language examples for C#, Go, Python, and TypeScript — using the OpenFeature SDK and flagd providers.

   Connect to flagd

See also

• flagd documentation
• OpenFeature documentation
• Aspire Community Toolkit
• Aspire integrations overview