nextgentel / akka-tools   1.1.3

MIT License GitHub

Open source tools to simplify Akka event sourcing, journaling/persistence, serialization, clustering and sharding.

Scala versions: 2.12

NextGenTel - Akka Tools

Build Status Maven Central

This project contains various addons to Akka useful when working with:

  • Cluster
  • Sharding
  • Persistence and Eventsourcing
  • Serializing

This code has turned out to be quite useful for NextGenTel and is used in production.


Akka akka-tools branch
2.5 2.5.x.x master
2.4 1.1.2 1.1


The changes can be found in this file.

Migration from akka-tools 1.0.x

Info about how to migrate your source from akka-tools 1.0.x to 1.1.x can be found in

Below is a summary of the various modules


akka-tools-persistence's main purpose is to make Akka Persistence more easy to use.

The main components are:

  • GeneralAggregate - which is built on top of PersistentActor
  • GeneralAggregateView - which is built on top of PersistentQuery

It includes features like:

  • Separation of aggregate, view and state(machine)
  • both aggregate and view understands the same events and uses the same "state machine"
  • integrated cluster/sharding-support
  • Simplified AtLeastOnceDelivery-support
  • Automatic starting and stopping (of idle) aggregates and views
  • Automatic working view that supports getting the current state (ie. to be used from REST) and the full event history (nice when debugging)


akka-tools-json-serializing is an Akka Serializer implementation that uses Jackson Json.

Json is a good match for evolving data-structures, but this serializer also supports coded data-structure-upgrading


akka-tools-jdbc-journal is a JDBC journal-plugin for Akka Persistence.

When used together with akka-tools-json-serializing, it also writes the json as 'plain-text' so that a human can understand the written data.

It supports Persistence Query with EventsByTagQuery (Also multiple tags in the same stream) amongst others


akka-tools-cluster contains cluster-related utilities like:

  • dynamic seedNode-resolving
  • Split-brain detection and recovering
  • ClusterSingletonHelper


examples contains example code