Javalin is a lightweight framework for Java and Kotlin languages, with no external dependencies apart from the embedded web-server (jetty) and running of plugins for JSON mapping and template rendering.

While Kotlin, the open-source general purpose programming language for JVM and Android, combines object-oriented and functional programming features, Java as the traditional language of Android development, can't be easily sidelined, at least for the foreseeable future.

Javalin offers a lightweight REST API library, or microframework with no concept of MVC, supporting WebSockets, template engines, and static file-serving which makes it useful in building RESTful API back end and serving index.html with static resources.

The framework started as a fork of the Spark framework for Java and Kotlin, but now has been heavily influenced by Koa.js web framework.

The version 2.0 of Javalin, brings support for HTTP/2 and async requests, and full interoperability between the Java language and Kotlin, with the template functionality moved to a single ctx.render() function that employ the correct engine, based on file extension.

The CRUDhandler addition removes the boilerplate from creating standard CRUD (create, read, update, delete) APIs, and the new functionalities of modularization of JSON and template allow developers to plug-in own mapping/rendering engines.

Javalin 2.0 is now available and can be downloaded from the project’s page.

Javalin, the lightweight framework for Java and Kotlin hits version 2.0



Javalin is a lightweight framework for Java and Kotlin languages, with no external dependencies apart from the embedded web-server (jetty) and running of plugins for JSON mapping and template rendering.

While Kotlin, the open-source general purpose programming language for JVM and Android, combines object-oriented and functional programming features, Java as the traditional language of Android development, can't be easily sidelined, at least for the foreseeable future.

Javalin offers a lightweight REST API library, or microframework with no concept of MVC, supporting WebSockets, template engines, and static file-serving which makes it useful in building RESTful API back end and serving index.html with static resources.

The framework started as a fork of the Spark framework for Java and Kotlin, but now has been heavily influenced by Koa.js web framework.

The version 2.0 of Javalin, brings support for HTTP/2 and async requests, and full interoperability between the Java language and Kotlin, with the template functionality moved to a single ctx.render() function that employ the correct engine, based on file extension.

The CRUDhandler addition removes the boilerplate from creating standard CRUD (create, read, update, delete) APIs, and the new functionalities of modularization of JSON and template allow developers to plug-in own mapping/rendering engines.

Javalin 2.0 is now available and can be downloaded from the project’s page.

No comments