How to get started with Wow framework quickly?

Use the Wow Project Template to bootstrap a DDD project integrated with Spring Boot. It provides a structured setup with domain modeling and testing utilities, reducing initial configuration time.

Wow vs Axon Framework for CQRS and event sourcing?

Wow offers a reactive programming model and declarative APIs tailored for Kotlin/Java with Spring Boot, while Axon has a broader ecosystem and longer track record. Wow may be better for teams already invested in Spring and preferring modern reactive approaches.

How does Wow handle failed events or retries?

Wow includes an event compensation dashboard with mechanisms for retrying failed events, as shown in the execution sequence diagrams. It allows manual intervention and automated retry policies for error handling.

What are the real-world performance numbers for Wow?

The README provides detailed TPS benchmarks, such as 59,625 average TPS for AddCartItem in SENT mode, with PDF reports and graphs. These demonstrate high throughput but vary based on wait strategy and infrastructure.

Can I use Wow without Kotlin or only with Java?

Yes, Wow supports both Kotlin and Java, as evidenced by separate examples for Order Service (Kotlin) and Transfer (Java). The declarative API is designed to work seamlessly with both languages.

How to test sagas in Wow effectively?

Use the SagaVerifier for unit testing sagas with a Given-When-Expect pattern, as shown in the CartSagaTest example. It allows mocking events and expecting specific commands, ensuring reliable saga behavior.

Is Wow suitable for small microservices or only large systems?

Wow is optimized for complex, scalable microservices with event-driven architectures. For small, simple services without audit trails or domain complexity, its overhead might be unjustified compared to lighter frameworks.

Wow — Event-Sourced Microservices Framework

What is Wow?

Wow is a framework for developing reactive microservices based on Domain-Driven Design (DDD), Command Query Responsibility Segregation (CQRS), and Event Sourcing. It provides a structured architecture to handle complex business domains by separating command and query models, persisting state changes as events, and enabling high-performance, scalable applications. The framework integrates with Spring Boot and offers tools for testing, observability, and event compensation.

Target Audience

Backend and microservice developers, particularly those working in Kotlin or Java ecosystems, who are building complex, event-driven systems that require scalability, audit trails, and strict domain modeling.

Value Proposition

Developers choose Wow for its cohesive integration of DDD, CQRS, and Event Sourcing patterns into a single, reactive framework. It stands out with its declarative API, comprehensive testing utilities, built-in observability, and proven high-performance benchmarks, reducing the boilerplate and complexity typically associated with these architectural patterns.

Modern Reactive CQRS Architecture Microservice development framework based on DDD and EventSourcing | 基于 DDD & EventSourcing 的现代响应式 CQRS 架构微服务开发框架

Use Cases

Best For

Building event-driven microservices with complex business logic
Implementing Domain-Driven Design in Kotlin or Java applications
Creating systems that require full audit trails and event replayability
Developing high-throughput command processing services
Structuring applications with a clear separation of commands and queries
Integrating Event Sourcing and CQRS with Spring Boot ecosystems

Not Ideal For

Projects with simple CRUD requirements and no need for audit trails or complex business logic
Teams prioritizing strong consistency over eventual consistency, as event sourcing introduces latency
Organizations lacking expertise in Domain-Driven Design or event-driven architectures
Applications needing integration outside the JVM ecosystem, due to tight Spring Boot coupling

Pros & Cons

Pros

Declarative Domain Modeling

Enables fluent definition of aggregates, commands, and events in Kotlin/Java, as shown in the modeling patterns and test code snippets for CartSpec and OrderTest.

High-Performance Command Processing

Supports configurable wait strategies (SENT, PROCESSED) with proven TPS benchmarks, such as 59,625 average TPS for AddCartItem in SENT mode, detailed in performance reports.

Comprehensive Testing Suite

Provides AggregateVerifier and SagaVerifier for unit testing with a Given-When-Expect pattern, facilitating 80%+ test coverage, as demonstrated in the example domain tests.

Built-in Observability

Integrates with OpenTelemetry for tracing and monitoring across distributed systems, highlighted in the observability section with visual dashboards.

Event Compensation Dashboard

Includes tools and a dashboard for handling failed event processing and retries, with detailed sequence diagrams and execution flows in the documentation.

Cons

Steep Learning Curve

Requires understanding of DDD, CQRS, Event Sourcing, and Reactive Programming, as listed in preconditions, making it inaccessible for teams new to these concepts.

Infrastructure Complexity

Deployment examples depend on Redis, MongoDB, and Kafka, indicating significant setup and operational overhead for distributed systems.

Spring Boot Lock-in

Tightly integrated with Spring Boot 3.x/4.x and Spring WebFlux, limiting adoption in non-Spring environments or with alternative JVM frameworks.

Eventual Consistency Trade-offs

Event sourcing inherently introduces eventual consistency, which may not suit applications requiring immediate data synchronization, despite compensation mechanisms.

Frequently Asked Questions

What is Wow?

Target Audience

Value Proposition

Use Cases

Best For

Building event-driven microservices with complex business logic
Implementing Domain-Driven Design in Kotlin or Java applications
Creating systems that require full audit trails and event replayability
Developing high-throughput command processing services
Structuring applications with a clear separation of commands and queries
Integrating Event Sourcing and CQRS with Spring Boot ecosystems

Not Ideal For

Projects with simple CRUD requirements and no need for audit trails or complex business logic
Teams prioritizing strong consistency over eventual consistency, as event sourcing introduces latency
Organizations lacking expertise in Domain-Driven Design or event-driven architectures
Applications needing integration outside the JVM ecosystem, due to tight Spring Boot coupling

Pros & Cons

Pros

Declarative Domain Modeling

Enables fluent definition of aggregates, commands, and events in Kotlin/Java, as shown in the modeling patterns and test code snippets for CartSpec and OrderTest.

High-Performance Command Processing

Supports configurable wait strategies (SENT, PROCESSED) with proven TPS benchmarks, such as 59,625 average TPS for AddCartItem in SENT mode, detailed in performance reports.

Comprehensive Testing Suite

Provides AggregateVerifier and SagaVerifier for unit testing with a Given-When-Expect pattern, facilitating 80%+ test coverage, as demonstrated in the example domain tests.

Built-in Observability

Integrates with OpenTelemetry for tracing and monitoring across distributed systems, highlighted in the observability section with visual dashboards.

Event Compensation Dashboard

Includes tools and a dashboard for handling failed event processing and retries, with detailed sequence diagrams and execution flows in the documentation.

Cons

Steep Learning Curve

Requires understanding of DDD, CQRS, Event Sourcing, and Reactive Programming, as listed in preconditions, making it inaccessible for teams new to these concepts.

Infrastructure Complexity

Deployment examples depend on Redis, MongoDB, and Kafka, indicating significant setup and operational overhead for distributed systems.

Spring Boot Lock-in

Tightly integrated with Spring Boot 3.x/4.x and Spring WebFlux, limiting adoption in non-Spring environments or with alternative JVM frameworks.

Eventual Consistency Trade-offs

Event sourcing inherently introduces eventual consistency, which may not suit applications requiring immediate data synchronization, despite compensation mechanisms.

Frequently Asked Questions

Wow

What is Wow?

Overview

Use Cases

Best For

Not Ideal For

Pros & Cons

Pros

Cons

Frequently Asked Questions

Related Projects

Found a gem we're missing?

Wow

What is Wow?

Overview

Use Cases

Best For

Not Ideal For

Pros & Cons

Pros

Cons

Frequently Asked Questions

Related Projects

Found a gem we're missing?