Flags SDK by Vercel

Flags SDK by Vercel, developed by the creators of Next.js, is a free and open-source library designed to implement feature flags and A/B tests in applications. It is versatile, working seamlessly with any flag provider or custom setup. The SDK ensures compatibility with App Router, Pages Router, and Middleware, making it suitable for various Next.js and SvelteKit projects.

The Flags SDK functions as an intermediary between your application and the flag source, promoting best practices and maintaining website performance. It supports flexible integrations, allowing the use of any flag provider or even none at all. This flexibility makes it ideal for strategic releases, controlled rollouts, and A/B testing, enabling developers to experiment confidently.

Setting up the Flags SDK is straightforward, thanks to its simple declarative API. Developers can easily define and use feature flags within their code. For example, a flag can be declared and used to toggle features based on conditions such as random values or other criteria.

In summary, Flags SDK by Vercel is a robust tool for managing feature flags and conducting A/B tests, with easy integration and flexible setup options that cater to various development needs.