Why should you care?

You care about this when basic CRUD and RabbitMQ are working and you need reliable events, auth, or gradual migration from a legacy monolith.

See it live — copy this example

Create a Web API project (dotnet new webapi), paste the code, then run dotnet run.

await _db.Orders.AddAsync(order);
await _outbox.AddAsync(new OutboxMessage("OrderPlaced", payload));
await _db.SaveChangesAsync(); // atomic: order + outbox row

Run Example »

This lesson uses terminal or setup steps. Run commands on your computer — the live editor appears on coding lessons.

What happened?

• The example shows Event Sourcing wired into Payment Service.
• Read each line, run it locally, then change one setting and observe what breaks or improves.
• That is how teams learn in production too — small experiments, not big bang rewrites.

Try it yourself

1. Open or create the ShopNest project area for Payment Service.
2. Apply the Event Sourcing pattern from the lesson example.
3. Run dotnet build && dotnet run (or docker compose up when the lesson uses containers).
4. Change a string or route in the example and save — watch Swagger or the RabbitMQ Management UI update.
5. Break the code on purpose (remove a semicolon), read the error message, then fix it.

Remember

Event Sourcing connects to Payment Service in ShopNest Cloud-Native. Practice by editing the example yourself — do not only read. Move on when you can explain this topic in your own words without looking.

Real-world: Swiggy order → restaurant → rider flow

When a customer confirms food order, events notify restaurant prep and rider dispatch. No single 30-second HTTP chain.

Outcome: Restaurant promos deploy without taking down payment processing.