How can I debug Python 3 code in Visual Studio Code?

Python 3 debugging works well also. It is a little confusing as there are two different places to specify the path: settings.json and launch.json.

I recommend using Don Jayamanne's Python Extension. After installing it, you have to configure the path to the interpreter you want to use it with.

Python Version used for Intellisense, autocomplete, linting, formatting, etc.

The same Python interpreter is used for intellisense, autocomplete, linting, formatting, etc. (everything other than debugging). The standard interpreter used is the first Python interpreter encountered in the current path. If a different version is to be used, this can be configured in one of two ways:

Configure the path to the python interpreter in the User Settings file (settings.json) as follows. Ensure to specify the fully qualified name of the python executable. "python.pythonPath": "c:/python27/python.exe"

Configure the path to the Python interpreter in the Workspace Settings file (settings.json) as follows. Ensure to specify the fully qualified name of the Python executable. "python.pythonPath": "c:/python27/python.exe" Python Version used for debugging

Details on configuration settings for debugging can be found here Debugging. Simply provide the fully qualified path to the python executable in the "python" setting within the configuration settings in the launch.json file as follows:

{
    "name": "Python",
    "type": "python",
    "request": "launch",
    "stopOnEntry": true,
    "program": "${file}",
    "pythonPath": "c:/python27/python.exe",
    "debugOptions": [
        "WaitOnAbnormalExit",
        "WaitOnNormalExit",
        "RedirectOutput"
    ]
}

There is a setting trigger within the setting file:

For Python default (which is 2.7 for now)

"python.pythonPath": "python",

For Python 3:

"python.pythonPath": "python3",

Use the following command to check the Python version:

import sys
  print(sys.version)

As of September 2016 (according to the GitHub repository documentation of the extension), you can just execute a command from within Visual Studio Code that will let you select the interpreter from an automatically generated list of known interpreters (including the one in your project's virtual environment).

Execute:

Python: Select Workspace Interpreter

For later version, just:

Python: Select Interpreter

in the command palette (F1 for Windows, Ctrl + Shift + P for macOS).

Then select one of the Python interpreters shown in a drop down list. And that's it. Your settings.json file will be edited automatically to point to the interpreter you selected.

Source: Don Jayamanne's extension's documentation at GitHub

_{Note: Since I couldn't comment to the accepted answer I copied some of my answer to a similar question.}

We can configure the debug in Python 3 in file settings.json:

Menu File → Preferences → Settings (file ~/.config/Code/User/settings.json) (User Settings)

{
  ...
  "python.pythonPath": "python3",
}

Also, verify that the launch.json file already has the following configuration:

"configurations": [
  {
    "name": "Python: Current File (Integrated Terminal)",
    "type": "python",
    "request": "launch",
    "program": "${file}",
    "console": "integratedTerminal"
  },
  ...
]