Building an Event-Driven Web API Using Channels in .NET

Yohan Malshika

6 min read

·

Nov 17, 2025

--

1

Share

Press enter or click to view image in full size

When you build a Web API, sometimes you need to handle work that should not block the main request.

For example:

• A user uploads a file, and you want to process it in the background.
• A new order is created, and you want to send an email or update inventory later.
• A message is received, but you don’t want the API to wait for the message to finish processing.

These are event-driven scenarios. Instead of doing everything immediately, your system reacts to events and processes them asynchronously.

Usually, people use external tools like RabbitMQ, Kafka, or Azure Service Bus for this. However, for smaller or medium-sized systems, these tools can be too complex and expensive to manage effectively.

That’s where Channels in .NET come in — a built-in and lightweight way to create your own in-memory event-driven system.

What Is an Event-Driven System?

In an event-driven system, everything starts with an event.
An event is simply something that happened.

For example:

• “OrderCreated” — means a new order was placed.
• “FileUploaded” — means a…