How do I add environment variables to launch.json in VSCode

I'm successfully passing them using the env property in launch.json:

{
  "version": "0.2.0",
  "configurations": [
    {
      "type": "pwa-node",
      "request": "launch",
      "name": "Launch Program",
      "skipFiles": [
        "<node_internals>/**"
      ],
      "program": "${workspaceFolder}/index.js",
      "env": {
        "TEST_VAR": "foo"
      }
    }
  ]
}

Important Note (see comments)

env has been renamed to environment in current versions of VSCode, the syntax is also changed. See the answer of @Gabriel below. – burito

this is working

just add the following

"env": { "NODE_ENV": "development" }

"configurations": [
    {
        "type": "node",
        "request": "launch",
        "name": "Launch Program", //TODO: cmd as launch program
        "skipFiles": [
            "<node_internals>/**"
        ],
        "program": "${workspaceFolder}\\index.js",
        "env": {
            "NODE_ENV": "development"
        }
    }
]

Version 1.49.1

You can add env variables by using the env property in your launch.json file or by using the envFile property with the value being the location of your .env file.

Warning: If you already have a .env file it auto includes it. (per denislexic comment)

env example:

{
  ...
   "env": { "PORT": "4000" }
  ...
}

envFile example:

{
  ...
  "envFile": "${workspaceFolder}/server/.env",
  ...
}

Like this, under your OS:

        "osx": {
            "MIMode": "lldb",
            "environment": [{"name": "DYLD_LIBRATY_PATH", "value": "/Users/x/boost_1_63_0/stage/lib/"}]
        },

Since late 2016 you can also use the envFile for Node.js projects:

The VS Code Node debugger now supports to load environment variables from a file and passes them to the node runtime. https://github.com/Microsoft/vscode/issues/15964

Also see: Load environment variables from external file (node):

To use this feature, add an attribute envFile to your launch configuration and specify the absolute path to the file containing the environment variables:

For Asp.Net Core projects, this feature isn't supported natively by vscode but it has recently been added to the omnisharp vscode extension. This feature is available since September 10, 2018 via v1.16.0.

It worked for my django project using the envFile variable. You can checkout this link: https://code.visualstudio.com/docs/editor/debugging

{
   "version": "0.2.0",
    "configurations": [
        {
            "name": "Python: Django",
            "type": "python",
            "request": "launch",
            "program": "${workspaceFolder}/project/manage.py",
            "args": [
                "runserver"
            ],
            "django": true,
            "envFile": "${workspaceFolder}/project/Server/settings/local.env"
        }
    ]
}

I had this same problem and it turns out I had a .env file in my project root which was overriding the launch.json settings. YOU'VE BE WARNED. :)

For reference, I came across a similar issue (in 2020, long after the bug mentioned in the accepted answer above was fixed) for a different language and would like to point out something:

Accoding to Microsoft's documentation on launch configurations, many common options, including "env" are not requried features for all different debugging/run environments - that is to say, it seems to me that it is not VS Code that 'provides' the option for environment variables, but rather, the choice of the specific debugger extension to implement this feature. Therefore, either

• An unexpected crash of the debugging application
• the warning Property "env" is not allowed

may occur because the particular language/debugger you are using doesn't support or hasn't implemented handling of environment variables.

As qbiq has said, probably a quick workaround for this if the environment variables are not going to change across launches would be to export them and run VS Code with this specific set of variables set.

On june 2020 this is still very misleading and broken on OSX Catalina 10.15.5. I am using VSCode insiders with CodeLLDB extension version 1.5.3:

Version: 1.47.0-insider
Commit: 0913b1aa43191d8af0ccb4a133d9a8d7c1a81d69
Date: 2020-06-23T09:38:28.751Z (1 day ago)
Electron: 8.3.3
Chrome: 80.0.3987.165
Node.js: 12.13.0
V8: 8.0.426.27-electron.0
OS: Darwin x64 19.5.0

When launching the debugger with the env keyword on launch.json I get this:

So in a nutshell, using "env" directive in launch.json will show up the message in the screenshot. This will prevent running the debugger, surprising lacking feature, but fair enough.

But then, using environment instead of env, there's no error message popping up but the environment variables are not available on the runtime being debugged, so getenv(whatever) does not return the actual value for that key :-!

as a workaround, you can set environment variables when starting VSCode, for example, using this little powershell script:

param(
 $vars = @{}
)

$vars.Keys | % {
    write-host "adding env variable: $_=$($vars[$_])"
    [Environment]::SetEnvironmentVariable($_, $vars[$_], "Process")
}
$ver = "0.1.0"
& "$env:LOCALAPPDATA\Code\app-$ver\Code.exe"

Save it as vscode.ps1 and call it from commandline, like this:

powershell ".\vscode.ps1 -vars @{ 'NODE_ENV'='test'; 'SOMETHING'='else' }"