How to add Environment Variables in Visual Studio

Let’s go step-by-step to add and use Environment Variables in Visual Studio for your C# project 

 Step 1: Open Project Properties

1. In Visual Studio, right-click on your project name in Solution Explorer.

2. Select Properties.

3. Go to the Debug tab (on the left).

 Step 2: Add Environment Variables

1. Scroll down to Environment Variables section (under “Debug” tab).

2. Click Add or directly type in key-value pairs like this:

   SUPABASE_URL = https://xyzcompany.supabase.co
   SUPABASE_KEY = eyJhbGciOiJIUzI1NiIsInR5...
   

3. Save changes (Ctrl + S).

 These variables will now be available at runtime when you debug the project.

 Step 3: Use Them in Code

You already have the correct code 

private static async void InitializeSupabaseAsync()
{
    var url = Environment.GetEnvironmentVariable("SUPABASE_URL");
    var key = Environment.GetEnvironmentVariable("SUPABASE_KEY");

    SupabaseClient = new Client(url, key, new Supabase.SupabaseOptions
    {
        AutoConnectRealtime = true
    });

    await SupabaseClient.InitializeAsync();
}

 When you run or debug your project, url and key will automatically read values from the environment variables you added.

 Step 4 (Optional): Set System-wide Environment Variables

If you want these variables available outside Visual Studio, for example when running from command line:

1. Press Windows + R → type sysdm.cpl → Enter.

2. Go to Advanced → Environment Variables.

3. Under User variables → click New.

4. Add:

   Variable name: SUPABASE_URL
   Variable value: https://xyzcompany.supabase.co
   
   Variable name: SUPABASE_KEY
   Variable value: eyJhbGciOiJIUzI1NiIsInR5...
   

5. Click OK and restart Visual Studio.

 Tip (For ASP.NET / Web Projects)

If your project is an ASP.NET Core app, you can also use appsettings.json and User Secrets instead of environment variables:

Example:

{
  "Supabase": {
    "Url": "https://xyzcompany.supabase.co",
    "Key": "eyJhbGciOi..."
  }
}

And access them in C#:

var url = Configuration["Supabase:Url"];
var key = Configuration["Supabase:Key"];