Introduction
KiCad in the Browser (PCBJam) runs KiCad in a browser tab. It uses KiCad's own C++ code, compiled to WebAssembly with Emscripten, so it isn't a lookalike editor or a read-only viewer. Emergence Engineering, a software shop in Hungary, builds it. The project started as a side project by their CTO, Viktor, who has an electrical engineering background. It reached a wider audience through a Show HN post on Hacker News, and the public demo at demo.pcbjam.com is labelled an early-access alpha.
I care about one question here. Can you open a real KiCad project on a machine where you can't install anything, and do useful work on it? Mostly yes, with caveats that come from its alpha status. I give it 5.2 out of 10: an impressive port, good for viewing and quick edits, and too early to trust with a board that has a fab deadline.
Key Features
Real KiCad compiled to WebAssembly
The team ported wxWidgets (the UI toolkit KiCad is built on) to WebAssembly and wrote their own WebGL rendering layer instead of emulating desktop OpenGL. The GitHub repo pulls KiCad source in as a git submodule, and the developers say they carry roughly 150 modified core KiCad files and plan to push changes upstream over time. The code is GPL-3.0, the same as KiCad, and the wxWidgets port files are LGPL v2.
In practice this means file fidelity. Your .kicad_pcb and schematic files are parsed by KiCad's own code, so you avoid the conversion losses you get with third-party viewers. The menus, dialogs and hotkeys match what you already know from the desktop app.
Schematic, layout, DRC, 3D and Gerbers
The creator describes the full loop: draw a schematic, move to PCB layout, run DRC, then export. The 3D viewer works, and the Open CASCADE module behind it is lazy-loaded so it doesn't slow the first page load. DRC and rendering run on multiple threads through Emscripten pthreads, which is why DRC on a small board feels close to native. Gerber export is listed, so you can go from an idea to fab files in a browser tab, at least in principle.
Local projects, nothing uploaded
You can open your own KiCad project from disk. According to the site, nothing is uploaded. PCBJam imports a copy into the browser as an editable project and leaves your original files alone. When you're done, you save and download the result as a .zip. This matters if you work on closed hardware and your employer has rules about where design files can go. I'd still check the network tab yourself before loading anything under NDA, because an alpha's privacy claim is only as good as its current build.
Example boards
The demo ships with example projects, so you can see whether it runs well on your machine before touching your own files. That takes seconds, and it's the quickest way to judge performance on your hardware.
Browser support and download size
The full app (two editors plus libraries) is about 30MB, or 24MB with Brotli compression. That's a one-time wait on a decent connection and a real cost on a slow one. Per the developer, Firefox runs it best and Chrome is fine. Safari works, with problems caused by its threading limits. iOS currently fails because it runs out of memory, so an iPad isn't an option yet.
Pricing Breakdown
| Plan | Price | What you get |
|---|---|---|
| Free alpha demo | $0 | KiCad in the browser, example boards, open your own KiCad projects |
| Planned paid tier (not live) | Around $30/month, per the developer on Hacker News | Aimed at bigger or closed projects; no feature list published |
Right now it costs nothing. The site itself shows no pricing page and no roadmap. In the Hacker News thread, the developer said the plan is a free tier plus a paid tier of around $30 a month for bigger or closed-source projects, with self-hosting, enterprise features, AI features and native or mobile builds mentioned as future work. Treat all of that as intent rather than a price list.
The comparison you should run is against desktop KiCad, which is free and always will be. For $30 a month to make sense, PCBJam will need to offer something the desktop app can't, such as shared projects, review links or hosted storage. None of that is visible in the demo today, so I can't judge whether the paid tier will be worth it.
Pros & Cons
Pros
- No install. It works on a locked-down work laptop, a library PC or a borrowed machine.
- It runs actual KiCad code, so projects open as KiCad intends and the UI is familiar.
- Example boards let you test performance in seconds.
- Project files stay local, per the site, and you export your work as a .zip.
- Open source under GPL-3.0, so the port can't simply vanish behind a paywall.
- Free to try.
Cons
- Early-access alpha. The developer admits several bugs remain, and you should expect crashes and missing pieces.
- No public pricing or roadmap on the site. The only pricing signal is a Hacker News comment.
- Very little documentation on the demo page. You'll lean on what you already know about KiCad.
- Around 24MB to 30MB to download before you can start.
- Safari is shaky and iOS doesn't work.
- I haven't tested performance on large, many-layer boards. Browser memory limits make that the obvious risk.
- Plugin and Python scripting support isn't documented, so don't count on your usual action plugins.
Who Is It For
The best fit is someone reviewing a board rather than building one. A colleague sends you a KiCad project, you're on a machine without KiCad, and you need to check a footprint, look at the 3D render or run DRC. PCBJam handles that without an install, and you can close the tab afterwards.
It also suits teaching. A workshop where half the room has managed laptops and the other half has a mix of operating systems becomes simpler when everyone opens the same URL in Firefox. Open-source hardware maintainers could point contributors at it as a way to look at a design before installing the full toolchain.
It's a poor fit for anyone shipping boards on a schedule. If you're sending Gerbers to a fab house this week, use desktop KiCad, where crashes are rare and your libraries, plugins and settings are already set up. It's also no use on an iPad today.
Verdict
PCBJam is a serious bit of engineering. Getting KiCad, wxWidgets, OpenGL and a threaded DRC running in a browser tab at close to native speed is hard, and the team did it in the open under the GPL. For viewing, reviewing and demoing KiCad boards on machines where you can't install software, it already works and costs nothing.
It's still an alpha. The docs are thin, the business model is a forum comment, and I wouldn't trust it with a production board until it has a stable release and a clear record on large projects. My recommendation: bookmark KiCad in the Browser (PCBJam) for quick looks and design reviews, try it with the example boards and one of your own projects in Firefox, and keep desktop KiCad for real work. I'll revisit the 5.2/10 once pricing is published and the paid tier shows what it adds beyond the free desktop app.
