Important: This news article covers an old version of Javalin (v2.7.0). The current version is v6.1.3.
See the documentation page for up-to-date information.

Configure your WebSocketServletFactory

It’s now possible to configure the object which creates WebSocket connections in Javalin. This can be done through app.wsFactoryConfig():

app.wsFactoryConfig { wsFactory ->
    wsFactory.policy.maxTextMessageSize = 1234;
    wsFactory.policy.idleTimeout = 1234;

This gives you access to a lot of low level settings for WebSockets. For details, see the Jetty docs.


  • Added some missing overrides in EmbeddedJavalin
  • Made it possible to use nested paths in CrudHandler
  • Bumped Jetty to the latest version