🪄 Ecommerce with the Critter Stack 🛒

🤔 What is this repository?

This repository's goal is to demonstrate how event-driven concepts and orthogonal patterns don't require convoluted or custom implementations which dampen your team's software development. By leveraging the Critter Stack, which consists of Wolverine + Marten from JasperFX, you can super-charge your .NET development while simplifying your codebase and test cases.

Get ready to unlock success with Event Driven Architectures through the Critter Stack!

🛒 Ecommerce

The "domain" of this effort is ecommerce, as it provides an assortment of use cases that vary in complexity, ranging from listing the details of a single product to the ever-shifting dynamics of the retail supply chain.

We will use an assortment of features in the Critter Stack long with using modern .NET conventions to best help you understand how to leverage these techniques in your own software projects.

🚧 Roadmap

WIP of the WIP. :)

🏞️ Value Streams

Value Streams are a core concept in Team Topologies. To grossly simplify, think departments, divisions, or teams within a company. That is, organizing business and technology teams for fast flow.

These value streams are how the overall .NET solution will be broken down. For example, as of 2025-06-11, there is a Catalog and Supply Chain solution folders to separate the teams value streams of our imaginary ecommerce business.

🏞️ Value streams and their responsibilities (chart)

Value Stream	Responsibility
📝 Catalog	Product definitions, SKUs, attributes
📺 Channels	Marketplace listings, syncs, channel-specific logic
📨 Orders	Customer purchases, order lifecycle
🏪 Checkout	Shopping cart, validation, checkout flow
📦 Inventory	Stock levels, reservations, fulfillment readiness
📒 Procurement	Supply chain, purchase orders, restocking
🛤️ Fulfillment	Shipping, delivery tracking, warehouse orchestration
💳 Payments	Payment gateway, capture, refunds
⚠️ Promotions & Pricing	Discounts, price changes, campaigns
🔎 Search & Discovery	Read-optimized catalog/index views
💼 Vendor Portal	B2B portal, performance dashboards and stats
🧓🏻 Customer Accounts	Identity, profile, registration
💁🏻‍♂️ Support	Tickets, complaints, return handling
📫 Notifications	Email, SMS, webhooks, system messaging

🏞️ Modules across the value streams (chart)

An example of various proposed modules in this system, highlighting some technologies and techniques that are being used or under proposal.

Value Stream	Module(s)	Wolverine	Marten	EF Core	CRUD or ES	CQRS	Additional Notes
📦 Inventory	Receiving Shipments	✅	✅	⛔	ES	✅	...
📦 Inventory	Warehouse Stocks	✅	✅	⛔	ES	✅	...
📝 Catalog	Products	✅	✅	⛔	ES	✅	...
📝 Catalog	Taxonomy	✅	✅	⛔	CRUD	✅	Postgres document store
📺 Channels	Listings	✅	✅	⛔	ES	✅	...
📺 Channels	Marketplace Integrations	✅	✅	⛔	ES	✅	...
🏪 Checkout	Storefront	...	...	...	...	...	Either frontend or BFF
🏪 Checkout	Shopping Cart	✅	✅	⛔	ES	✅	...
📨 Orders	TBD	✅	✅	⛔	ES	✅	Sagas showcased
💳 Payments	TBD	✅	✅	⛔	ES	✅
🧓🏻 Customer Accounts	TBD	✅	✅	⛔	ES	✅	Multitenancy showcased
🧓🏻 (Legacy) Catalog	Catalog	✅	⛔	✅	CRUD	⛔	No Critter Stack at all possibly
🧓🏻 (Legacy) Catalog	Sku Management	✅	⛔	✅	CRUD	⛔	No Critter Stack at all possibly
🤔 More TBD	...	...	...	...	...	...	...

➡️ Diagrams

Work-in-progress.

I would like to outline some of the business workflows as well as the technical aspects like architecture.

Receiving Shipments workflow

This diagram visualizes the ReceivingShipments workflow and the typical status transitions for a ReceivedShipment aggregate. It can be visualized as a simple state machine:

stateDiagram-v2
    [*] --> Created : ReceivedShipmentCreated
    Created --> Receiving : ReceivedShipmentLineItemAdded
    Receiving --> Receiving : ReceivedShipmentLineItemAdded
    Receiving --> Receiving : ReceivedShipmentLineItemQuantityRecorded\n(not all items received)
    Receiving --> Received : ReceivedShipmentLineItemQuantityRecorded\n(all items received)
    Receiving --> Received : ReceivedShipmentMarkedAsReceived
    Received --> PutAway : ReceivedShipmentPutAway
    Created --> [*]
    Receiving --> [*]
    Received --> [*]
    PutAway --> [*]

Status Transitions Explained

• Created: Shipment initiated, but no items yet.
• Receiving: At least one line item added. Remains here as line items and their received quantities are added.
• Received: All line items have been recorded as received (automatically, or via explicit "Mark as Received").
• PutAway: The shipment is assigned to a putaway lot/location—no further receiving actions possible.

Note:

• Returning to [ * ] just represents an end state; in practice, transitions are unidirectional.

🛠️ Local Development

WIP. To launch Docker with the all profile, use this docker-compose command:

docker-compose --profile all up -d

🏫 Resources

Blogs, articles, and other resources will be listed here. 🚧

Tools Used

I've been a large fan of JetBrains' suite of Integrated Development Environments (IDEs) for the better part of a decade. That includes their dotnet IDE called Rider which is used to work on this effort.

👷‍♂️ Maintainer

Erik "Faelor" Shafer

• linkedin: in/erikshafer
• blog: event-sourcing.dev
• youtube: yt/event-sourcing
• bluesky: erikshafer