Why should you care?

You care about this when ShopNest services must react to events without blocking the HTTP request that started the flow.

See it live — copy this example

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

public record OrderPlacedEvent(Guid OrderId, decimal Total);

await publishEndpoint.Publish(new OrderPlacedEvent(order.Id, order.Total));

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 Publish-Subscribe Pattern wired into Order 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 Order Service.
2. Apply the Publish-Subscribe Pattern 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 number in the example and run again — predict the output first.
5. Break the code on purpose (remove a semicolon), read the compiler error, then fix it.

Remember

Publish-Subscribe Pattern connects to Order 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: Flipkart Big Billion Day checkout

During peak sales, Order and Payment services scale independently. RabbitMQ buffers spikes so Payment workers catch up without blocking the mobile app.

Outcome: Checkout returns in under 500ms while payment completes in the background — shoppers see clear status updates.