Question: Can you recommend a solution that provides pre-built user authentication and database integration for my NextJs project?

Supabase is an open-source Firebase alternative that includes a Postgres database and built-in user authentication. It supports Next.js and other frameworks and offers a variety of tools like password hashing, third-party provider support and real-time data synchronization. Supabase also comes with a data management dashboard and a variety of templates to get you started, including a Next.js Starter.

Another good option is Staarter, a Next.js SaaS boilerplate that offers pre-configured core features for scalable SaaS projects. It includes strong authentication and authorization, subscription management with Stripe, Paddle, or LemonSqueezy, and full localization support. Staarter also offers a modern stack, type-safe API, code generators, and strong security, so it's a good choice for SaaS product development.

For a more lightweight approach, Kobble offers a no-code authentication portal and a collection of tools for user management, access control and quotas. It integrates with Next.js and supports a variety of OAuth providers, making authentication easy. Kobble also offers payment integration with Stripe and a built-in frontend with pre-built authentication and customer portals. It's a good option for developers who want to quickly get a SaaS application up and running.

Last, SaaSBold is a full-stack SaaS boilerplate built on Next.js, React and Node.js. It includes features like multidimensional authentication, payments and subscriptions with Stripe and LemonSqueezy, transactional emails, and an admin dashboard. SaaSBold also supports internationalization and includes SEO and performance optimizations, so it's a good option for SaaS product development.