---
title: "How can I detect async deadlocks in a .NET Core web API?"  
description: "How can I detect async deadlocks in a .NET Core web API?"  
author: "John Smith"  
published: 2026-09-21  
canonical: https://answers.mindstick.com/qa/117253/how-can-i-detect-async-deadlocks-in-a-net-core-web-api  
category: "troubleshooting"  
tags: ["Debugging", ".NET", "async", "performance"]  
reading_time: 1 minute  

---

# How can I detect async deadlocks in a .NET Core web API?

## Understanding the Problem

Async deadlocks in .NET are sneaky. They happen when you mix blocking calls like `.Result` or `.Wait()` with asynchronous code, and the synchronization context tries to reclaim a thread that’s already stuck waiting. In a web API, this often surfaces as a request that never returns, leaving connections pooled and threads exhausted.

### Common Triggers

- Calling `async` methods from synchronous event handlers without proper context handling.
- Using `ConfigureAwait(false)` incorrectly in library code that later needs the context.
- Deadlocks between `async` methods that lock on shared objects while awaiting.

The first step is instrumenting your application. Tools like **PerfView**, **dotTrace**, or the built-in **DiagnosticSource** events can reveal threads stuck in wait states. Pay attention to threads parked in `Task.Wait()` or `Task.Result` calls during request processing.


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Original Source: https://answers.mindstick.com/qa/117253/how-can-i-detect-async-deadlocks-in-a-net-core-web-api

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