lustefaniak / akka-viz   0.1.7

Contributors Wanted MIT License GitHub

A visual debugger for Akka actor systems (wip)

Scala versions: 2.11


a visual debugger for Akka actor systems (experimental)

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Current version is built agains akka 2.4.10.


Latest version is: Download

To get started you need to add dependencies for "monitoring" jar:

resolvers += Resolver.bintrayRepo("lustefaniak", "maven")

libraryDependencies += "com.blstream.akkaviz" %% "monitoring" % "0.1.7"

After that you must configure your application to run with AspectJ weaver.

SBT plugin

Latest version is: Download

Simpler way is to use sbt plugin, which will preconfigure required bits, in your project directory create file project/akkaviz.sbt with:

resolvers += Resolver.url("lustefaniak/sbt-plugins", url(""))(Resolver.ivyStylePatterns)

addSbtPlugin("com.blstream.akkaviz" % "sbt-akka-viz" % "0.1.7")

Sample project

Please check lustefaniak/akka-viz-demo for simple, preconfigured SBT project.


REPL and Actor messaging graph

Actor hierarchy and Actor details tab

Message archive

FSM monitoring


  • see which actors exchange messages on a graph
  • monitor internal state via reflection
  • track FSM transitions
  • monitor actor creation
  • display messages in realtime (with contents) for selected actors
  • filter messages by class
  • delay processing of messages
  • display information about exceptions in actors and used supervisor strategies



To change one of the akka-viz default settings create application.conf file as defined in Typesafe Config documentation

Default settings are:

akkaviz {
  internalSystemName = akka-viz
  interface =
  port = 8888
  bufferSize = 10000
  maxSerializationDepth = 3
  inspectObjects = false
  autoStartReporting = true
  enableArchive = true
  cassandra {
    keyspace = akkaviz
    preparedStatementCacheSize = 100
    session {
      contactPoint =

Message archive

Akka-viz can use Cassandra database to store all messages so they could be replayed in the frontend for easier debugging.

To use it make sure akkaviz.enableArchive = true and akkaviz.cassandra points to correct Cassandra configuration.

You need to manually create keyspace and tables. Execute included DDL via cqlsh


We supply a few demos with the source code, so you can explore without hooking up to an existing ActorSystem.

Clone project and run with demo/reStart in SBT. Go to http://localhost:8888 in your favourite browser and play around!

Monitoring existing systems

Include jar in classpath of your app and run your main(). Server should be listening on http://localhost:8888.

Under the hood

To hook into Akka's internals, we use AspectJ (capturing actor creation, intercepting of messages). WebSocket handling is provided by Akka HTTP and Akka Streams. Filtering is done per client; slowing down of message processing, however, affects the whole system. Frontend is powered by Scala.js, Scala.Rx and ScalaTags.

Serialization for messages

We're using custom-made serialization with help of upickle for transporting the messages to frontend clients. To serialize some specific type of message - ie. your custom class, that you want to have displayed in web frontend - you have to implement a AkkaVizSerializer.