Lumen vs Rails API: What are the differences?

What is Lumen? The stunningly fast PHP micro-framework by Laravel. Laravel Lumen is a stunningly fast PHP micro-framework for building web applications with expressive, elegant syntax. We believe development must be an enjoyable, creative experience to be truly fulfilling. Lumen attempts to take the pain out of development by easing common tasks used in the majority of web projects, such as routing, database abstraction, queueing, and caching.

What is Rails API? Rails for API only applications. Rails::API is a subset of a normal Rails application, created for applications that don't require all functionality that a complete Rails application provides. It is a bit more lightweight, and consequently a bit faster than a normal Rails application. The main example for its usage is in API applications only, where you usually don't need the entire Rails middleware stack nor template generation.

Lumen and Rails API belong to "Microframeworks (Backend)" category of the tech stack.

"API" is the primary reason why developers consider Lumen over the competitors, whereas "Great for quick decoupled apps" was stated as the key factor in picking Rails API.

Lumen and Rails API are both open source tools. Lumen with 6.29K GitHub stars and 833 forks on GitHub appears to be more popular than Rails API with 5.27K GitHub stars and 293 GitHub forks.