How do I get Visual Studio Code to trust our self-signed proxy certificate?

This is a terrible answer (not very secure), but appears to be the current Microsoft official answer. Use "http.proxyStrictSSL": false in your settings.json file.

This should work to get around the issue of installing extensions inside a corporate network, but I'd recommend disabling the setting if you are going to be working from home/coffee shop and not connected to the corporate VPN.

https://github.com/Microsoft/vscode/issues/3492

I was having the same issue, not when installing an extension, but when a certain extension was trying to download data. Adding "http.proxyStrictSSL": false to my settings file did not work. Disabling SSL is also a really bad idea.

The resolution was to install the Visual Studio Code win-ca plugin which makes trusted Windows certificates available to extensions.

There is actually a better way:

Since VS Code is built on Chromium the "proxy settings should be picked up automatically" from Google Chrome/Chromium. So if you add your self-signed certificate in Chrome/Chromium by going to:

1. chrome://settings/privacy
2. Manage certificates
3. Authorities / Import
4. Select and import your certificate (pem-file)
5. Restart VS Code

I was able to download VS Code extensions despite being behind a corporate proxy.

Remark: Ubuntu 18.04 and VS Code works only with Chrome and not Chromium.