Type-safe feature flags for Node.js and React

• Define environment-aware defaults in an application-owned registry.

• Resolve flags on the server and pass typed snapshots to React components.

• Supports Node.js, Bun, Cloudflare Workers, Vercel Edge Runtime, Deno Deploy, and other edge runtimes.

• Browser/client React components (FlagProvider, Flag, useFlag) consume pre-resolved snapshots.

• Create typed React bindings once from your application's registry for seamless integration.

• Local environment variables can be used to force flags on or off during development.

Flagkeeper is a type-safe TypeScript feature flag library designed to streamline the management of feature flags in your Node.js and React applications. It allows you to define defaults that are aware of different environments, ensuring consistent flag resolution across your development, staging, and production setups. The library enables you to resolve flags on the server-side and then pass these resolved flags as typed snapshots to your React components, enhancing type safety and developer experience.

Key features include:

• Environment-Aware Defaults: Define specific default values for flags based on the environment (e.g., development, staging, production).

• Server-Side Resolution: Resolve all flags on the server to ensure a consistent state is passed to the client.

• Type Safety: Leverages TypeScript to provide strong typing for flag keys and their values, reducing runtime errors.

• React Integration: Offers components like FlagProvider, Flag, and hooks like useFlag for easy integration within React applications.

• Runtime Compatibility: Works seamlessly with various Node.js environments, including Cloudflare Workers and Vercel Edge Runtime, by allowing you to pass environment objects during resolution.

• Local Overrides: Facilitates local development by allowing you to override flag values using environment variables without altering the registry defaults.

With Flagkeeper, managing feature flags becomes a more robust and predictable process, contributing to smoother development cycles and more reliable application deployments.