Learn CQRS and Event Sourcing through interactive koans in multiple programming languages.
Mixter is an open-source educational project that teaches CQRS (Command Query Responsibility Segregation) and Event Sourcing through interactive koans—coding exercises where users fix failing tests to learn concepts step-by-step. It implements a social messaging domain to demonstrate how these architectural patterns work in practice, helping developers move from theory to hands-on experience.
Developers and software architects who want to learn or deepen their understanding of CQRS and Event Sourcing patterns through practical, language-agnostic exercises.
Mixter offers a unique, hands-on approach to learning complex architectural patterns by providing koans in multiple languages, allowing developers to focus on concepts rather than setup, with clear progression and example solutions.
CQRS and Event Sourcing Koans
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Supports C#, Java 8, Scala, PHP, and JavaScript, enabling developers to learn CQRS/Event Sourcing in their preferred language without conceptual barriers.
Uses interactive koans with a CLI script (./run and ./next) that guides users through fixing failing tests, reinforcing patterns through practical coding.
Implements a social messaging domain to illustrate aggregates, event publication, and decision projections in a relatable, concrete context.
Originally created for a Mix-IT workshop and refined through feedback, ensuring the exercises are effective for group or self-paced learning.
Omits explicit command handlers for simplicity, as admitted in the README, which may not reflect full production scenarios or advanced CQRS setups.
The KoanCli script requires static test counts per step, making it inflexible for adding custom exercises or adapting to different learning paces.
Targets specific versions like Java 8, which may not align with modern development environments using newer language features or frameworks.