Eclipse Ditto™ 2.2.0



The main improvements and additions of Ditto 2.2.0 are:

  • Filter for twin life-cycle events like e.g. "thing created" or "feature deleted" via RQL expressions
  • Possibility to forward connection logs via fluentd or Fluent Bit to an arbitrary logging system
  • Add OAuth2 client credentials flow as an authentication mechanism for Ditto managed HTTP connections
  • Enable loading additional extra JavaScript libraries for Rhino based JS mapping engine
  • Allow using the dash `-` as part of the "namespace" part in Ditto thing and policy IDs

The following notable fixes are included:

  • Policy enforcement for event publishing was fixed
  • Search updater cache inconsistencies were fixed
  • Fixed diff computation in search index on nested arrays

The following non-functional work is also included:

  • Collect Apache Kafka consumer metrics and expose them to Prometheus endpoint
Architectural Issues

Ditto's codebase is implemented in Java. By default Java objects are mutable which does not work well in highly scalable, message driven architectures, as possible side-effects during runtime may occur when concurrently modifying objects. Because of that the Ditto team decided to use immutable objects wherever and whenever possible. Immutablity of the objects is ensured in unit tests.

Ditto's model modules and also the Ditto Java client are OSGi bundles so that they may be used in OSGi environments without much effort. The model modules are configured to be checked by a "binary compatibility checker" in the Maven build so that APIs are not broken unintentionally.

On a level higher than the model, Ditto uses a microservice based architecture. As Ditto's microservices are interacting via an event driven approach, Ditto provides a very modular setup on the microservice level meaning that single services must be not started at all if their functionality is not needed. Another benefit from this architecture is that the services may be scaled horizontally if more resources are required.

Ditto utilizes the CQRS and EventSourcing pattern and mainly uses "inserts" (append only) into the database in favor to "updates" in order to get a better performance when doing database writes. The only exception is the "search" microservice which uses traditional CRUD in order to update its search index.

Security Issues

There are no security issues known at the time of this writing.

Non-Code Aspects

Ditto comes with:

Conforms To UI/UX Guidelines
Not applicable (project doesn't provide UI)
Usability Details

Ditto does not provide a UI.

End of Life



Ditto is able to process AMQP 1.0, AMQP 0.9.1, MQTT 3.1.1 and MQTT 5 messages which are all standardized (IoT) protocols.

Ditto can use JSON Web Tokens specified by RFC 7519 in order to extract "subjects" (e.g. a user-id) to use for the access control to twins.

Ditto's API documentation is defined using the OpenAPI specification 3.0.0 allowing both creation of an interactive HTML-based documentation and creation of skelettons for various programming languages based on that specification.


Users of Ditto ask their questions via these channels:

  • The Gitter chatroom of Ditto
  • Directly via GitHub issues (the Ditto teams labels with "question")
  • A Stackoverflow tag "eclipse-ditto" on which community quersions are answered by our committers
  • The mailing-list ( contains mainly administrational topics regarding the Ditto project

Ditto seeks for a good integration with Eclipse Hono in order to being able to create digital twins for all devices connected via Hono. The Ditto team is also in regular discussion with the Hono team.

Some of the Ditto team are committers in the Eclipse IoT Packages project aiming to simplify deployment and integration between Eclipse Hono and Ditto.