---
title: "Explain the difference between in-process and out-of-process hosting."  
description: "Explain the difference between in-process and out-of-process hosting."  
author: "ICSM Computer"  
published: 2025-06-16  
updated: 2025-06-17  
canonical: https://www.mindstick.com/forum/161721/explain-the-difference-between-in-process-and-out-of-process-hosting  
category: "c#"  
tags: ["c#"]  
reading_time: 2 minutes  

---

# Explain the difference between in-process and out-of-process hosting.

**[Explain the difference](https://www.mindstick.com/forum/156125/can-you-explain-the-difference-between-organic-and-paid-results) between in-[process](https://yourviews.mindstick.com/story/1525/7-important-factors-that-may-affect-the-learning-process) and out-of-process hosting.**

## Replies

### Reply by ICSM Computer

In ASP.NET Core, **in-process** and **out-of-process** refer to how your application is hosted and run with respect to the web server (like IIS or Kestrel). Here's a clear breakdown:

### In-Process Hosting

- The ASP.NET Core app **runs inside the IIS worker process** (`w3wp.exe`).
- No separate process for the Kestrel server is created.
- **Better performance** due to avoiding reverse proxy overhead.

#### Configuration:

In your `.csproj` file:

```xml
<AspNetCoreHostingModel>InProcess</AspNetCoreHostingModel>
```

#### Request Flow:

```plaintext
Browser → IIS (w3wp.exe) → ASP.NET Core Middleware
```

#### Pros:

- **Faster** because there is no inter-process communication.
- **Simpler setup** – everything runs in a single process.

#### Cons:

- Runs only on **Windows with IIS**.
- Limited to IIS features and constraints.

### Out-of-Process Hosting

- ASP.NET Core app runs in its **own process** (like `dotnet.exe`).
- IIS (or Nginx/Apache) acts as a **reverse proxy** forwarding requests to the app.

#### Configuration:

In your `.csproj` file:

```xml
<AspNetCoreHostingModel>OutOfProcess</AspNetCoreHostingModel>
```

#### Request Flow:

```plaintext
Browser → IIS (w3wp.exe) → Kestrel (dotnet.exe) → ASP.NET Core Middleware
```

#### Pros:

- **Cross-platform** (Linux, macOS, Windows).
- Full control over Kestrel and app lifetime.

#### Cons:

- Slight performance penalty due to the proxy hop.
- More configuration complexity (especially on Linux).

### Comparison Table

| Feature | In-Process | Out-of-Process |
| --- | --- | --- |
| Process | `w3wp.exe` (IIS worker) | Separate `dotnet.exe` |
| Performance | Faster | Slightly slower |
| OS Support | Windows only | Cross-platform |
| Reverse Proxy Needed | No | Yes (IIS, Nginx, Apache) |
| Hosting Model Tag | `InProcess` | `OutOfProcess` |

### When to Use Which?

- **Use In-Process** for Windows + IIS deployments where performance matters.
- **Use Out-of-Process** if you:

   - Need cross-platform support
   - Want more control over the app process
   - Are using Kestrel behind a reverse proxy


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Original Source: https://www.mindstick.com/forum/161721/explain-the-difference-between-in-process-and-out-of-process-hosting

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