Avoid capturing original SynchronizationContext

Context: By default, await captures the current SynchronizationContext and resumes on it. ConfigureAwait(false) avoids this, which can prevent deadlocks and improve performance.

using System.Threading.Tasks;

public class LibraryCode
{
    public async Task<string> GetDataAsync()
    {
        // In library code, we don't need to return to original context
        string result = await FetchAsync().ConfigureAwait(false);
        return result;
    }

    private async Task<string> FetchAsync()
    {
        await Task.Delay(100);
        return "data";
    }
}

When to use

• In library code that does not need to return to the original context.
• To avoid deadlocks when .Result or .Wait() is used (though those should be avoided).

Real-world usage example

ASP.NET Core: In ASP.NET Core, there is no SynchronizationContext, so ConfigureAwait(false) is not necessary but does no harm.

Example: ConfigureAwait FAQ

Related sections

• 9.6 ConfigureAwait false
• 9.6.2 Use in library code