Skip to content
Get packs

Guide · Open source

How to use modular-monolith-with-ddd: clone, build and read the code

Updated · written with AI from the project's own documentation and checked against our catalogue data

modular-monolith-with-ddd is an MIT-licensed, C# .NET example application. It runs as one deployable program split into separate modules, and it applies Domain-Driven Design to a Meeting Groups domain modeled on Meetup.com. This guide shows you how to get the code, what to look at first, and which parts the README says are in or out of scope, so you can study it for your own architecture decisions.

Modular Monolith with DDDkgrzybek/modular-monolith-with-ddd · ★ 14.1k · MIT

Quick start

  1. 1Clone the repository. Run the git clone command from the README to copy the project to your machine.
  2. 2Read the README table of contents. Use the numbered sections to find the domain description and architecture notes before opening code.
  3. 3Read the Meeting Groups domain. Review the business rules for Member, Meeting Group and Meeting in section 2 so the code has context.
  4. 4Study the architecture sections. Read the module level view and CQRS processing sections to see how modules communicate.
  5. 5Look at the tests. Review the unit tests for the domain model and the integration tests to see how each layer is verified.
  6. 6Check build requirements. The README lists no prerequisites, so confirm the .NET and tooling needs in the repository before building.

What the project is and who it is for

The README describes the repository as a full Modular Monolith .NET application with a Domain-Driven Design approach. Its stated purpose is to show these ideas in a complete implementation that is ready to run in production, not a small proof of concept.

It fits developers learning DDD tactical patterns in C#, teams comparing a modular monolith against microservices, engineers who want to see CQRS and unit and integration tests together, and students reading architecture decisions in a realistic codebase.

  • Good fit: learning tactical DDD patterns, comparing modular monolith and microservices structure, studying CQRS with tests
  • Poor fit: a quick, minimal starter project, a deployment guide, or strategic DDD guidance (the README lists these as out of scope)

Install modular-monolith-with-ddd by cloning and building

The project uses a clone-and-build approach. The README gives the clone command below. It does not list prerequisites, so check the repository for build requirements before you start.

Replace nothing in the command: it clones the repository from its GitHub address into your current folder.

git clone https://github.com/kgrzybek/modular-monolith-with-ddd

Find your way around the repository

The README's table of contents is the best map of the codebase. Start with the Domain section to understand the Meeting Groups model, then read the Architecture section to see how modules are organized.

The domain centres on three entities: Member, Meeting Group and Meeting. Only an Organizer of a Meeting Group can create a new Meeting, and a Meeting must have at least one Host.

  • Section 2 (Domain): description, conceptual model and event storming
  • Section 3 (Architecture): C4 model, module level view, module communication, CQRS request processing
  • Section 3.10 and 3.13: unit tests for the domain model and integration tests
  • Section 3.15: event sourcing

Study the DDD and CQRS patterns

The README says the project presents the implementation of DDD tactical patterns and shows how module requests are processed via CQRS. Read the domain model principles section alongside the code to connect the written rules with the classes that enforce them.

Business rules in the Meeting Groups domain, such as attendee limits that send extra members to a Waitlist and guest limits set per Meeting, are good examples to trace through the code.

  • Section 3.4: Module requests processing via CQRS
  • Section 3.5: Domain model principles and attributes
  • Section 3.12: architecture unit tests

Know what the repository does not cover

The README is explicit about its limits. It lists deployment process, infrastructure and containerization as out of scope, along with strategic DDD patterns and domain distillation. If you need those, use other resources alongside this project.

The README also says the architecture is one of many possible solutions and should not be copied without considering your own business problem and constraints.

  • Out of scope: deployment, infrastructure, containerization, strategic DDD patterns, domain distillation
  • The README links a separate React front-end repository, which is a different project

What people use it for

  • Learning how tactical DDD patterns such as aggregates and domain rules look in a C# codebase
  • Comparing a modular monolith structure with a microservices design for a team decision
  • Studying how CQRS and unit and integration tests are applied together in one project
  • Using a realistic codebase as material for an architecture course or study group

Frequently asked questions

Is modular-monolith-with-ddd free to use?

Yes. The repository is licensed under MIT, so you can use it under that licence's terms. The README's license section covers the details.

What programming language is modular-monolith-with-ddd written in?

It is written in C# for .NET. The README describes it as a full Modular Monolith .NET application.

How do I install modular-monolith-with-ddd?

The project uses a clone-and-build approach. Run git clone https://github.com/kgrzybek/modular-monolith-with-ddd, then build it. The README does not list prerequisites, so check the repository for build requirements.

Is this a good starter project for a beginner?

Not really. The README says it is intentionally a full application and not a simple one, with many entities and use cases. Beginners may prefer a smaller sample to learn the basics first.

Does the project explain how to deploy it?

No. The README lists deployment process, infrastructure and containerization as out of scope, so this repository is not a deployment guide.

How does it compare with other DDD and clean architecture examples?

The README says many sample applications are too simple, unfinished or old, and this project aims to fill that gap with a full implementation. Related projects it is often compared with include ddd-guide, eShopOnContainers, CleanArchitecture and jasontaylordev/CleanArchitecture.

New agent skills, repos and AI tools — every week

The best new skills and open-source projects, the fastest-growing repos, and one free prompt. Five minutes to read. Unsubscribe anytime.

Our verdict

Use modular-monolith-with-ddd if you want a complete, realistic C# example of a modular monolith with DDD, CQRS and tests to study. Pick something smaller if you need a quick starter, a deployment guide, or strategic DDD advice, since the README excludes those.

Install options & downloads