How do I list a private Github repo as a "dependency" in package.json? I tried npm's Github URLs syntaxes like ryanve/example, but doing npm install in the package folder gives "could not install" errors for the private dependencies. Is there a special syntax (or some other mechanism) for depending on private repos?

It can be done via https and oauth or ssh.

https and oauth: create an access token that has "repo" scope and then use this syntax:

"package-name": "git+https://<github_token>:x-oauth-basic@github.com/<user>/<repo>.git"

or

ssh: setup ssh and then use this syntax:

"package-name": "git+ssh://git@github.com:<user>/<repo>.git"

(note the use of colon instead of slash before user)