Question: I need a flexible framework that enables custom component integration and extensible authentication for my web application.

If you're looking for a flexible foundation that lets you add your own components and extend authentication for your web app, Supabase is a great option. It's an open-source Firebase alternative that includes a Postgres database, RL Secure user authentication and edge functions to run your own code. Supabase supports frameworks like Next.js, Svelte and Flutter, so it's good for whatever development style you prefer. It also includes real-time data synchronization, large-file storage and vector embeddings to integrate machine learning models.

Another good option is Clerk, a full-stack user management service that handles authentication and user management with a collection of embeddable UI components and flexible APIs. Clerk supports multifactor authentication, advanced security and session management, so it's secure and easy to use. It also supports multi-tenancy, with customizable roles and permissions, so it can accommodate different organizational needs.

If you want a full CMS and app foundation, check out Payload. Payload is built with the TypeScript programming language and React framework, and it includes features like AI-generated content, visual editing and reusable authentication. It can accommodate custom component integration, single sign-on integration and access control, so it's a good foundation for building your own business apps. Payload is available under the MIT License and offers free self-hosted and paid options.

Last, Backendless offers a low-code app builder with a visual UI builder, codeless logic and direct API integration. It includes real-time databases, more than 18 third-party authentication providers and customizable email and push notifications. Backendless lets you deploy your app in a variety of ways, including serverless and self-hosted infrastructure, so it's good for building high-performance apps with a minimum of hassle.