A lightweight REST API library

Javalin is a true microframework with only one required dependency: SLF4J (logging).

By default Javalin also depends on Jetty, but you can exclude it (or use the javalin-without-jetty artifact) if you want to use a different Webserver (like Tomcat, etc).

Javalin also has plugins for JSON mapping, template rendering, and OpenAPI (Swagger), but they’re optional dependencies that you have to add manually.

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<dependency>
    <groupId>io.javalin</groupId>
    <artifactId>javalin</artifactId>
    <version>5.6.3</version>
</dependency>

Not familiar with Maven? Read our Maven tutorial.

implementation("io.javalin:javalin:5.6.3")

Not familiar with Gradle? Read our Gradle tutorial.

libraryDependencies += "io.javalin" % "javalin" % "5.6.3"

@Grab(group='io.javalin', module='javalin', version='5.6.3')

[io.javalin/javalin "5.6.3"]

'io.javalin:javalin:jar:5.6.3'

<dependency org="io.javalin" name="javalin" rev="5.6.3" />

If you want Javalin with testing tools, Jackson and Logback, you can use the artifact id javalin-bundle instead of javalin.

Javalin modules

There are multiple modules available for Javalin. All modules are released in sync with the core javalin module, you just have to replace the artifact id:

javalin - the core Javalin dependency (shown in the snippet above)
javalin-bundle - javalin, plus javalin-openapi, jackson and logback (good to get started fast)
javalin-openapi - the OpenAPI plugin and all required dependencies
javalin-graphql - the new GraphQL plugin
javalin-without-jetty - javalin with all jetty dependencies excluded and Jetty specific methods removed (useful for running on e.g. Tomcat)

Manual downloads

You can get the prebuilt jar from Maven Central.
You can get the source on GitHub, or download it as a zip.