Important: This news article covers an old version of Javalin (v3.6.0). The current version is v6.1.3.
See the documentation page for up-to-date information.


  • You can now document form params in the OpenAPI plugin (thanks to @TobiasWalle).
  • Added a simple Basic auth plugin (before-filter)


  • Added a debug log message for deserialization failures in Context#body<MyClass>() (thanks to @ksmith97).
  • Fixed error in logging missing path-params in OpenAPI plugin (thanks to @rafalsiwiec).
  • Javalin no longer warns about a missing logger if you have a higher version of SLF4J (thanks to @m-rossini).
  • Query-params can now contain equals signs (thanks to @pawel-piecyk).
  • Use byte[] instead of Byte[] in binary WebSocket messages (thanks to @dvtsants-alar).
  • Uploaded files are no longer buffered in RAM (thanks to @ryansusana).
  • Fixed a bug in JavalinVue when running from IDE using classpath.


  • Moved from Travis to GitHub actions for CI. All tests now run against Java 8 to 13 on OSX, Ubuntu and Windows.
  • Upgraded the Dokka (Java doc generator) plugin, should fix a bug where documentation for certain classes wasn’t generated
  • Bumped SLF4J and Jackson to the latest version