Explore the GitHub API

A short (100-line) JavaScript snippet to call the GitHub API from a browser UI – like a mini-Postman.

It runs in your browser like a browser extension. In fact, it can easily be turned into a browser extension.



  1. Show your bookmarks toolbar. In Chrome, … > Bookmarks > Show Bookmarks Bar. In Firefox, right-click in the title bar and click Bookmarks Toolbar.
  2. Drag this to the bookmarks toolbar: GitHub API Explorer


  1. Navigate your browser to
  2. Click the GitHub bookmark from your toolbar.

Alternative Setup

Copy this code to the browser console, or, if using Chrome, to a Snippet. For example:

  1. Press F12 (Windows) to open DevTools.
  2. Go to Sources > Snippets, click New Snippet.
  3. Give it a name, eg, “GitHub API Explorer”.
  4. Copy/paste the code from
  5. Save (Ctrl+S, Windows).

Alternative Usage

  1. Navigate your browser to
  2. Press F12 (Windows) to open DevTools.
  3. Run the code. If using a Snippet, there’s a Run button on the bottom right, or press Ctrl+Enter (Windows).
  4. Look for the popup window in the upper-left corner of your browser.

Check out GitHubAPIExplorer.js

Source Code


I’ve long been fascinated by the abillity to run arbitrary JavaScript against a website. This can be something simple, like scraping HTML. Or adding a “missing feature” to a website. I started learning about this around 15 years ago when I was using a time tracking website, but I found it tedious and error-prone. I was able to automate data entry with a simple piece of JavaScript.

Now I write more complex scripts like this one. I can add HTML/CSS popups and power them with JavaScript.

Browsers have gotten better at this, too. Chrome, for example, has a fairly complete set of developer tools for writing and debugging JavaScript.

There are a few options for running your JavaScript on someone else’s website:

[1] Address Bar

Address Bar

[2] Bookmarklet


[3] Chrome DevTools Console

Chrome DevTools Console

[4] Chrome Snippet

Chrome Snippet