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In today’s world, where everything is fast-paced, developers are constantly looking for ways to optimize their code performance. One way to achieve this is by using the async and await keywords in C#. In this article, we will dive into the concepts of async and await and learn how they can make our code more efficient.

What are async and await?

Async and await are two keywords in C# that help us to write asynchronous code. Asynchronous code is code that can execute in the background while the main thread continues to execute other code. This is important because it allows our code to perform multiple tasks simultaneously, without blocking the main thread.

The async keyword is used to mark a method as asynchronous. When a method is marked as async, it means that the method can run asynchronously, and it returns a Task or Task<T>. The Task object represents a unit of work that can be executed asynchronously. The Task<T> object represents a unit of work that returns a value of type T.

The await keyword is used to wait for a Task to complete. When we use the await keyword, the method that contains the await keyword is suspended until the Task completes. This allows the main thread to continue executing other code while the asynchronous task runs in the background.

Why should we use async and await?

Using async and await can improve the performance of our code in several ways. Here are a few benefits of using async and await:

  1. Improve responsiveness: Asynchronous code allows our application to remain responsive while it is performing time-consuming tasks in the background. This means that the user interface remains responsive and doesn’t freeze or hang.
  2. Improve scalability: Asynchronous code can handle more requests simultaneously, which makes it more scalable than synchronous code. This is especially important for web applications that need to handle multiple requests from different users at the same time.
  3. Improve resource utilization: Asynchronous code allows us to use resources more efficiently by running tasks in the background. This means that we can use the available resources more effectively and get more work done in less time.

How to use async and await?

Now that we understand what async and await are and why we should use them, let’s see how to use them in our code.

To use async and await, we need to follow these steps:

  1. Mark the method as async: We need to mark the method as async by adding the async keyword to the method signature. For example, public async Task<int> MyMethodAsync() {}
  2. Use the await keyword: We need to use the await keyword to wait for a Task to complete. For example, int result = await LongRunningTaskAsync();
  3. Call the method: We need to call the method as we would any other method. For example, int result = await MyMethodAsync();

Here’s an example of how to use async and await in C#:

public async Task<int> CalculateSumAsync()
int sum = 0;
await Task.Run(() =>
for (int i = 0; i < 1000000; i++)
sum += i;
return sum;

In the example above, the CalculateSumAsync method calculates the sum of the first one million numbers asynchronously using the Task.Run method. The method is marked as async, and the await keyword is used to wait for the Task to complete.


Async and await are powerful tools in C# that allow us to write asynchronous code and improve the performance of our applications. By using async and await, we can make our code more responsive, scalable, and efficient. If you’re not already using async and await in your code, it’s time to start!

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