One more click — it’s on the video below.
You bought an ultrawide.
Your videos didn't.
Ultrawider is a browser extension that fills the black side-bars on 21:9 and 32:9 monitors — a WebGL warp that stretches the edges and leaves faces round.
Looking for the extension…
In fullscreen a small popup appears — click Smoothie. That's the whole product.
One Firefox switch to flip first
- Click the puzzle-piece icon in the Firefox toolbar.
- Click Ultrawider.
- Choose “Always allow on every site”.
- Reload this page — the live tutorial appears here automatically.
We can't see the extension on this page. Not installed yet? Get it first, then come back:
Here's exactly what you'll see
Annotated mock-up — the real popup appears when you fullscreen a video.
- Open any video — YouTube is free forever.
- Press fullscreen.
- A small dark popup appears near the top — hover it, click Smoothie.
Set YouTube — same click, one time
Open any video, press fullscreen, click Smoothie. Ultrawider remembers it per site — set once, works forever.
YouTube is free forever. Twitch, Kick, Vimeo + more are Pro — $5/mo · $24/yr · $49 once, card or PayPal. See pricing →
Netflix, Disney+ and other DRM video can never work — we don't sell what we can't do.
Popup didn't appear?
- Make sure the video is actually fullscreen (press the ⛶ button in the player, or double-click the video).
- Move your mouse — the popup hides itself after a few seconds and comes back on movement.
- Check the extension is enabled: puzzle-piece icon in the toolbar → Ultrawider should be listed.
- Reload the video tab once after installing — tabs opened before the install don't have Ultrawider in them yet.
- Still nothing? Email hello@ultrawider.net — a human answers.
This page sent our server: browser type, extension version, screen shape and your anonymous install id — no cookies, no browsing history.
This screen is 16:9 — nothing to fill here.
Ultrawider fills side-bars that only exist on ultrawide monitors. This screen has none — that's geometry, not a bug.
Only have this 16:9 screen?
30-second favour — why did you install?
Thanks — that genuinely helps.
Honestly: Ultrawider can't do anything on a 16:9 screen, so feel free to uninstall it — no hard feelings.
How to uninstall
If our store listing made you think this works on 16:9 — that's a bug in our copy, tell us.
Install, then come back — this page turns into a live one-minute setup on your own screen.
What it does: fullscreen a video, click Smoothie in the popup, and the black side-bars are gone — edges stretched, faces untouched. Free on YouTube, forever. Live simulation: