How to add authentication to a React Native app with Better Auth

Authentication is a critical aspect of software development, and in React Native, it can start simply with an email-password flow but becomes complex when adding features like OAuth and account linking. Third-party providers like Clerk offer a solution by managing these complexities, allowing developers to avoid building an authentication system from scratch, though this comes with less control over user data. Better Auth, an open-source tool under the MIT license, offers an alternative by providing full control over data and the ability to self-host, along with an Expo plugin to ease mobile development. The guide explains how to build an Expo app with Better Auth, featuring email and password authentication, Google OAuth, session persistence, and protected routes, drawing parallels with Auth.js. In September 2025, Better Auth took over the maintenance of Auth.js, aiming to unify the ecosystem, suggesting that new projects should start with Better Auth. The guide also discusses setting up a development environment and navigating complexities such as Google OAuth integration, using Cloudflare Tunnel for public URLs, and ensuring protected routes within the app. By leveraging Better Auth, developers can manage user sessions and OAuth flows while retaining control over their data and enhancing the mobile development experience.