Determine GitHub usernames from email addresses, even if they are hidden

Usage no npm install needed!

<script type="module">
  import getGithubUsernames from '';


This is a tool to extract GitHub usernames from a known set of email addresses. It works even if the users' emails are not public.

The problem

It doesn't seem to be possible, either using the advanced search features, or the API, to directly look up a github username by a known email address, if that user has chosen not to make that email address public.

But, if they've associated it with their account, even if they haven't made it public, then git commits that they've made to repositories, that use that email address, are linked to their user accounts. And, as it happens, when you access the commits of that repo with the API, the usernames show up there, too.

So this tool works by creating a dummy repo, with git commits that use the email address that you have in your list. You can then push that repo up to GitHub, access the API to scrape the usernames, and then, if you want, delete the repo. So far, this isn't completely automated, but there's no reason it couldn't be.

Using get-github-usernames

Put the email addresses you want into a file named `users.txt, and then run ./index.js.

This creates a dummy git repository, and then makes a commit in it for each of the email addresses in the list.

When it's done (the following steps are manual so far):

  • push the dummy-repo up to GitHub; e.g. klortho/dummy-repo,
  • Access the GitHub API to get the usernames; e.g.
  • If there is a user that has that email address, then the username will be in the author/login field for that commit. Cross-reference to the email in the commit/author/email field.

To do

  • It shouldn't wipe out the dummy repo every time; it should first check it to see which emails already have commits, and then only add commits for those that don't.

  • Automate:

    • Pushing the repo to github (take the github repo url as a command-line param, or in a config file).
    • Reading the commits from the API and producing the report


See LICENSE.txt.