Browser extension (Firefox and Chrome) that widens GitHub pages between the native 1280 px default and the full viewport, in 1 % steps. The chosen value is persisted in storage.local and synced through storage.sync, so it follows you across devices when you are signed into your browser account.
In short: most existing "wide GitHub" extensions answer the question "narrow or full width?". GitHub Resizer answers "how wide?".
- Firefox: addons.mozilla.org/firefox/addon/github-resizer
- Chrome / Chromium / Edge / Brave: chromewebstore.google.com/detail/mipojddikhienkgpinpppjaaadkgmhlg
GitHub's main container (.container-xl) is capped at 1280 px. On a 1440p or 4K monitor that leaves large empty margins on every repo, PR, issue and code view.
GitHub Resizer adds a slider to the browser toolbar that lets you smoothly choose any width between GitHub's native default and the full width of your window - not just "on" or "off". Every open GitHub/Gist tab reflows live, without a reload.
The slider value is interpreted as "how much of the extra space above the 1280 px default should be used":
width = max(1280px, 1280px + slider/100 * (viewport - 1280px))
| Slider | 1280 px viewport | 1920 px viewport | 3840 px viewport |
|---|---|---|---|
| 0 % | 1280 (default) | 1280 (default) | 1280 (default) |
| 25 % | 1280 (viewport bound) | 1440 | 1920 |
| 50 % | 1280 (viewport bound) | 1600 | 2560 |
| 100 % | 1280 (viewport bound) | 1920 (full) | 3840 (full) |
On viewports up to 1280 px the extension produces exactly the same layout as default GitHub - no narrowing, no crushed sidebars, no visual change at all.
Existing extensions in this space are essentially a binary on/off toggle: GitHub's max-width is either removed entirely, or it isn't. GitHub Resizer takes a different approach.
| Feature | GitHub Resizer | Other "Wide GitHub" extensions |
|---|---|---|
| Width control | Slider (0–100 %, 1 % steps) | On / off toggle |
| Identical to default on ≤ 1280 px screens | Yes | – |
| Live updates, no reload | Yes | – |
Cross-device sync (storage.sync) |
Yes | – |
| Widens inner content column on Primer pages ¹ | Yes | Partial / no |
| Keeps README markdown responsive | Yes | – |
Modern GitHub pages have two layers: the outer page frame (the 1280 px cap) and the inner content column (where the file list, README or PR actually lives). Most "wide GitHub" extensions only stretch the outer frame, so you end up with a wide header but a narrow column floating in the middle.
GitHub Resizer removes both limits. GitHub builds those modern pages with the Primer <PageLayout> component through CSS Modules, which gives class names a build-specific hash (e.g. PageLayout-module__contentWrapper--abc123) that changes on every release - the extension matches them by prefix so it keeps working across GitHub updates.
Both store listings are currently under review. Until they're published, use the unpacked / packaged builds from this repo.
- Store: addons.mozilla.org/firefox/addon/github-resizer (under review)
- Load unpacked for development:
- Open
about:debugging#/runtime/this-firefox. - Load Temporary Add-on… → pick any file inside
Firefox/.
- Open
- Or install the packaged build:
github_resizer-firefox-1.0.0.zip.
- Store: chromewebstore.google.com/detail/mipojddikhienkgpinpppjaaadkgmhlg (under review)
- Load unpacked for development:
- Open
chrome://extensions. - Enable Developer mode (top right).
- Load unpacked → select the
Chrome/folder. - Pin the extension from the puzzle icon.
- Open
- Or install the packaged build:
github-resizer-chrome-1.0.0.zip.
Only the platform glue differs; content/, popup/ and the storage-sync logic are identical.
| Area | Firefox | Chrome |
|---|---|---|
| Extension API namespace | browser.* |
chrome.* |
browser_specific_settings (gecko id) |
Required | Removed |
action.theme_icons |
Supported | Removed (Firefox-only) |
| Icons | SVG | PNGs at 16/32/48/128 |
The width is stored under the key widthPercent in both storage.local (instant, always available) and storage.sync (cross-device when signed into your browser account). On load, sync wins if it has a value, otherwise local, otherwise the default. Changes are pushed to every open GitHub tab without a reload via storage.onChanged.
{ "widthPercent": 50 }| Setting | Value |
|---|---|
| Minimum | 0 % (= default GitHub) |
| Maximum | 100 % (= full viewport) |
| Step | 1 % |
| Default | 0 % |
storage- remember and sync the chosen width.- Host access to
github.comandgist.github.com- inject the CSS that widens the layout.
No background service worker, no network requests, no analytics.
MIT.