Firebase and Auth.js serve different needs and have their own advantages. Firebase is a complete app development platform that offers user authentication along with other features like storage, cloud functions, and monitoring. It supports a wide range of authentication methods including email and password, phone auth, magic links, two-factor authentication, and social identity providers. Firebase also has a generous free tier and a low cost per monthly active user. On the other hand, Auth.js is an open-source authentication library originally built for NextJS but now supports multiple frameworks like SvelteKit and SolidStart. It offers over 80 integrations for third-party identity providers and can be used with your own database. If you need an all-in-one platform with a generous free tier, Firebase might be the better choice. If you prefer an open-source solution with a high degree of flexibility and integration options, Auth.js could be more suitable.

Firebase offers a generous free tier with 50,000 monthly active users (MAUs) and beyond that, it charges a low price per MAU starting at $0.0055 and potentially decreasing to $0.0025 as you scale. Auth.js, being an open-source library, does not have any associated usage costs but requires you to manage your own infrastructure, which might incur additional costs depending on your hosting and database setup. If you are looking for a solution with predictable and potentially lower costs as you scale, Firebase might be more cost-effective. However, if you have the resources to manage your own infrastructure and want to avoid per-user costs, Auth.js could be a more economical option.

Auth.js offers better flexibility compared to Firebase. Auth.js is an open-source authentication library that supports over 80 integrations with various third-party identity providers and can be used with multiple frameworks such as Next.js, SvelteKit, and SolidStart. It allows you to use your own database, supporting MySQL, Postgres, MSSQL, and MongoDB. Firebase, while offering a wide range of authentication methods and integration with Google services, is more of a closed ecosystem. If you require a highly flexible and customizable authentication solution, Auth.js is the better option.

Auth.js, formerly known as NextAuth, is an open-source authentication library originally built for NextJS. It is free to use and offers over 80 integrations for various third-party identity providers such as Google, Facebook, Auth0, and Apple. Auth.js can also be used with your own database, supporting MySQL, Postgres, MSSQL, and MongoDB.

As of March 2024, Auth.js is compatible with Next.js, SvelteKit, and SolidStart.

Yes, you can use Auth.js with your own database. It supports MySQL, Postgres, MSSQL, and MongoDB.

Auth.js offers a variety of features including over 80 integrations with third-party identity providers like Google, Facebook, Auth0, and Apple. It is also compatible with multiple platforms such as Next.js, SvelteKit, and SolidStart, and supports various databases including MySQL, Postgres, MSSQL, and MongoDB.

Firebase is Google's app development platform that offers a comprehensive suite of features, including storage, cloud functions, monitoring, and user authentication. It supports multiple authentication methods such as email and password, phone authentication, magic links, two-factor authentication, and social identity providers like Google, Facebook, Apple, Microsoft, Twitter, GitHub, and OAuth access tokens.

Pros of Firebase include its ease of use, low price per monthly active user, a generous free tier, and easy SMS authentication. Currently, there are no user-generated cons for Firebase.

The free tier for Firebase includes 50,000 monthly active users (MAUs). Beyond that, pricing starts at $0.0055 per MAU and can go as low as $0.0025 per MAU as you scale to millions of users.

Firebase supports multiple authentication methods, including email and password, phone authentication, magic links, two-factor authentication, and social identity providers such as Google, Google Play Games, Facebook, Apple, Microsoft, Twitter, GitHub, and OAuth access tokens.