I built a projection mapping tool that runs in the browser — here's what 2,000 users taught me

Michele — Thu, 08 Oct 2026 11:52:39 +0000

Hi VJ Union 👋

I'm Michele, a developer from Italy, and for the past months I've been building 4mapper: a projection mapping and live visuals tool that runs entirely in the browser. No install, no drivers, no license dongle. You open a tab, connect a projector over HDMI, and start mapping.

This week it passed 2,000 registered creators, so it felt like a good moment to share it here, explain how it works, and ask for your honest feedback.

Why the browser?

Most mapping software is powerful, but it comes with friction: a big install, a specific OS, a license per machine. That's fine in a studio, but it's a pain when:

you're teaching a workshop on school computers where you can't install anything,
you want to test an idea in five minutes on whatever laptop is around,
you're starting out and don't want to spend hundreds of euros before knowing if you like mapping.

Modern browsers can do real-time WebGL, video decoding and multi-window output, so I wanted to see how far a web app could go.

What it does
Mapping

Quad warping with corner pinning, plus mesh warp for curved or irregular surfaces
Shape masks to cut the projection to the outline of an object
A separate output window you drag to the projector, while you edit on your laptop screen
Scenes, so you can prepare looks and switch between them during a live show

Content

Your own videos and images, plus a free library of ready-to-use loops
A Studio with small generators to create loops from scratch: tunnel, kaleidoscope, kinetic text, glitch, procedural patterns, color grading, a cube mapper…
Live widgets you can project: clock, weather, crypto tickers and more

Hardware

Arduino / ESP32 controllers over USB (open-source library), so you can trigger scenes with physical buttons and knobs

Free vs Pro
Free: 1 project, 10 files, 100 MB. Enough to learn and do small pieces.
Pro: a one-time payment (no subscription) for unlimited projects, 5 GB of storage, no watermark, 1080p export, and the controller support.

I'm a solo developer, so Pro is what keeps the project alive, but the free tier is meant to be genuinely usable, especially for students and workshops.

Where it's going

Things I'm working on next: better tools for multi-projector setups, more Studio generators, and a guide to choosing a used projector for mapping (a question I get all the time).

I'd love your feedback

You're exactly the people I'm building this for, so I'd really appreciate it if you tried it and told me:

What's missing that would stop you from using it in a real gig?
What feels slow or confusing?
Would a browser tool be useful for you as a backup or workshop setup?

Try it: 4mapper.com

Thanks for reading, and see you in the comments!

VJ UNION: Michele

I built a projection mapping tool that runs in the browser — here's what 2,000 users taught me