Release v0.12.1

Build Status Coverage Updates

Protean is a DDD and CQRS-based framework that helps you build Event-driven applications.

Get started with Installation and then get an overview with the Quickstart.


Protean’s documentation is Work-In-Progress - there are significant portions of functionality still missing. Refer to the contribution guide to help grow the documentation.


Protean helps you build applications that can scale and adapt to growing requirements without significant rework.

At its core, Protean encourages a Domain-Driven Design (DDD) approach to development, with support for artifacts necessary to express your domain succinctly and precisely. It also allows you to remain agnostic to the underlying technology by keeping implementation details out of view.

Protean can be thought of having three capabilities:

  • Service-Oriented - Develop your application as one or more subdomains that run independently as Microservices

  • Event-Driven: - Use events to propagate changes across subdomains or become eventually consistent within a Bounded Context.

  • Adapter-based: - Use Remain technology-agnostic by exposing Port interfaces to the infrastructure, with multiple adapters supported out of the box.

Read Foreword to understand Protean’s philosophy.


It is assumed that you have some prior knowledge about Domain-Driven Design (DDD) and Command Query Responsibility Segregation (CQRS) architectural patterns.

If you do not have sufficient background in these topics, you should go through standard texts to understand Protean’s behavior better.


Protean is currently under active development. APIs and interfaces are to be expected to change drastically and newer releases will almost certainly be backward incompatible.

If you are interested in using Protean for your project, you may want to wait for the announcement of first stable production-ready version. If you want to use the framework right now, drop us an email.

User Guide


API Reference

If you are looking for information on a specific function, class or method, this part of the documentation is for you.


The best way to track the development of Protean is through the the GitHub repo.