Firebase is a comprehensive app development platform that includes user authentication, while Lucia Auth is a specialized open-source authentication library. Firebase offers a generous free tier with 50,000 monthly active users and supports various authentication methods including email, phone, and social identity providers. It is known for its ease of use and low pricing per monthly active user. On the other hand, Lucia Auth is fully typed, works with any JavaScript runtime, and integrates well with multiple databases. The choice between Firebase and Lucia Auth depends on whether you need a full app development platform with integrated authentication (Firebase) or a flexible, open-source authentication library (Lucia Auth).

Firebase offers a generous free tier with 50,000 monthly active users, making it very cost-effective for small to medium-sized applications. Beyond the free tier, Firebase's pricing starts at $0.0055 per monthly active user and can go as low as $0.0025 per monthly active user at scale. Lucia Auth, being an open-source library, does not have a direct cost associated with its use, but you may incur costs for hosting and database services. Therefore, Firebase might be more cost-effective for applications with a large number of users due to its scalable pricing model.

Firebase is known for its ease of use and straightforward integration process, making it a popular choice for developers who want a quick setup. It provides extensive documentation and support for various authentication methods, including email, phone, and social identity providers. Lucia Auth, while also designed to be developer-friendly, requires more effort to integrate as it provides more flexibility and customization options. It is fully typed and works with any JavaScript runtime, which can be advantageous for developers who need this flexibility.

Firebase is highly versatile, offering a wide range of authentication methods including email and password, phone authentication, magic links, two-factor authentication, and social identity providers like Google, Facebook, Apple, and GitHub. It also integrates seamlessly with other Firebase services like storage, cloud functions, and monitoring. Lucia Auth, while more focused, offers versatility in terms of runtime compatibility and database integration. It works with any JavaScript runtime (Node.js, Bun, Deno, Cloudflare Workers) and integrates with various databases such as MongoDB, PostgreSQL, MySQL, and SQLite. The choice depends on whether you need a broader range of services (Firebase) or more specific runtime and database compatibility (Lucia Auth).

Firebase offers an excellent developer experience with its user-friendly interface, extensive documentation, and integrated services that simplify the development process. Its ease of use and comprehensive features make it a go-to choice for many developers. Lucia Auth, on the other hand, is fully typed and designed to work with any JavaScript runtime, offering a high degree of flexibility and customization. Developers who prefer open-source solutions and need to work with specific runtimes or databases might find Lucia Auth more suitable. Overall, Firebase is generally considered to provide a better out-of-the-box developer experience, while Lucia Auth offers more flexibility for those with specific needs.

Lucia Auth is an open-source authentication library designed to simplify session management. It supports various JavaScript runtimes, including Node.js, Bun, Deno, and Cloudflare Workers, and is fully typed. The library integrates with databases such as MongoDB, PostgreSQL, MySQL, and SQLite, as well as their respective ORMs and query builders.

Pros of using Lucia Auth include being open source, fully typed, and its compatibility with any JavaScript runtime. As of now, there are no user-generated cons listed for Lucia Auth.

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.