After 5 years of full-stack dev, I built a responsive-preview tool that could've helped me at work — would love your feedback

#webdev #productivity #showdev #frontend

I've been a full-stack web developer for 5+ years, both freelance and in-house. The whole time, one thing kept bugging me: checking the mobile/responsive layout — and especially showing it to a client. I always wanted a clean way to present it, ideally as a single video where both the desktop and the mobile version look good together.

About six months ago I finally sat down, sketched out the extension I wished existed, recently built it, and just put out a first version a few days ago. It's free.

What it does

It drops a real device frame on top of your live page, so you see the desktop and the mobile-adaptive layout at the same time, on one screen. The main things, all because I personally wanted them:

Synced scrolling, clicks and typing between the two views — interact with one, the other follows
Focus mode to hide everything but the device
Screenshots and local screen recording (mp4/webm) — so you can send a client one clean clip of "here's your site on both"
Settings saved across tabs, keyboard shortcuts
Fully local — no accounts, no tracking, nothing leaves the browser

Heads-up about the video below: it's the promo clip I made for the Chrome Web Store, so it's a little salesy. It's the only video I have right now, but it runs through most of the features quickly, so it's better than nothing for showing what it actually does.

Who it might help

Developers and designers checking responsive work
Freelancers and agencies presenting to clients (one nice video of both views)
People teaching web dev online — showing both layouts live on one screen

What I'd love your feedback on

I'd genuinely rather hear it from you than guess:

What's missing? What would make this a daily tool for you?
What features would you want as I keep building and scaling it?
And don't hold back the criticism — if you think it's pointless, tell me. If the idea has legs, that's what keeps me going.

I won't pretend otherwise — I'd be glad if it clicks for some of you and you keep using it. But the main ask here is the feedback. I'll do my best to listen to everyone and ship updates as often as I can. If you spot any bugs on your OS or browser version, let me know too.