Use environment specific variables in HTTP files

HTTP files provide a convenient way to test your API’s inside Visual Studio. In this post we'll look at a specific feature; the usage of environment-specific variables that let you seamlessly switch between environments without modifying your request files.

Getting started with .http files

Before diving into environment variables, let's understand the basics. When you create an ASP.NET Core project in Visual Studio 2022, you'll often find a .http file already in your solution. Here's a simple example:

Variables are defined with @variableName = value and referenced using {{variableName}}. The ### delimiter separates multiple requests in a single file.

Creating environment files

The real power comes when you externalize these variables into environment files. Visual Studio supports two types of environment files:

1. http-client.env.json (Shared)

This file contains environment configurations that are shared across your team and typically committed to source control.

2. http-client.env.json.user (Personal)

This file contains user-specific overrides and secrets. It should be excluded from source control (typically already in .gitignore by default).

Visual Studio searches for environment files intelligently:

1. It starts in the same folder as your .http file
2. If not found, it searches parent directories moving upward
3. It stops at the first http-client.env.json file it finds
4. The nearest file to your .http file takes precedence

This means you can have a single environment file at your solution root that applies to all .http files, or organize them by project or feature.

Selecting an environment

Once you've created an environment file, Visual Studio displays an environment selector dropdown in the upper-right corner of the .http file editor. You can:

• Press F6 to quickly access the selector
• Switch between environments with a single click
• Select "No Environment" to use only inline variables

Important Note: If you modify the environment file while an .http file is open, you may need to close and reopen the file, or switch to another environment and back, for changes to take effect.

More information

Use .http files in Visual Studio 2022 | Microsoft Learn

Executing HTTP requests through Visual Studio