2026-08-06T00:00:00.000Z

For forty years, serious CAD software has lived on the desktop. You installed a 5-gigabyte application, prayed the license server was up, and hoped the IT department didn’t lock down your machine. Browser “CAD” meant either a slow JavaScript approximation or a thin client streaming pixels from a server farm.

WebAssembly changed that. And the implications for anyone who drafts are bigger than most people realize.

What WebAssembly actually is

WebAssembly (WASM) is a low-level bytecode format that browsers can execute at near-native speed. Here’s the part that matters for CAD: you can compile existing C++ and Rust codebases to WASM and run them in the browser, unchanged.

That’s not a toy. The Rust CAD engine inside Cadelo — the same engine that runs as a native desktop app — is compiled straight to WASM. The browser is running the real thing, not a reimplementation.

What that means for rendering

CAD is GPU work. Lines, arcs, shaded solids, pan and zoom across a 10,000-entity drawing — that used to require native OpenGL.

WebGPU — the modern browser graphics API — is now available in Chrome, Edge, and Android, with Firefox and Safari following. It gives WASM CAD direct access to your GPU.
WebGL2 covers the rest as a fallback.

Cadelo uses wgpu, the same Rust graphics abstraction used by the desktop version. The rendering path is identical; only the driver changes. GPU-accelerated CAD in a browser tab, at desktop-app framerates.

What that means for files

DWG parsing is a hard problem — it’s a 40-year-old binary format with layers, blocks, xrefs, and more edge cases than anyone wants to count. Doing it in JavaScript would be a decade-long rewrite. Doing it in WASM means:

The existing, battle-tested Rust parser (acadifc, from the OpenAEC Foundation) runs in your browser
DWG R13 through R2018 reads and writes work exactly as they do on desktop
Parsing happens on your device — no uploading your engineering drawings to a stranger’s server

Why “no upload” matters

Almost every “free online CAD” tool before WASM worked by uploading your file to a server, converting it, and streaming the result back. That model has three problems:

Privacy — your floor plan, machine part, or patent-pending bracket now lives on someone else’s disk
Latency — every pan, zoom, and click is a round trip to a data center
Cost — the server has to render for you, so “free” means either ads out the wazoo or a paywall

WASM inverts all three: the file never leaves your machine, interaction is instant, and the compute is free (your own CPU and GPU). All a static site has to pay for is bandwidth — which is why a free, ad-supported model is sustainable.

The new CAD stack, summed up

Old stack	New stack (WASM)
5 GB desktop install	One browser tab
License server / dongle	Free, open source
Upload to render	Render locally on your GPU
One machine	Any device with a browser
Proprietary format lock-in	DWG/DXF/SVG/STL/STEP export

The honest caveats

WASM CAD isn’t magic:

First load is heavier — a full CAD engine is a few megabytes of WASM. Subsequent loads hit the cache.
Huge assemblies need memory; browsers are generous but not infinite. Fine for 2D drafting and moderate 3D.
Bleeding-edge GPU features arrive on desktop first, then browsers. The core workflows — 2D drafting, DWG/DXF, dimensioning — are already solid.

Try it

Cadelo puts a real CAD engine in your browser, free, with no account. Open a DWG, draft a part, export to DXF for your laser cutter — all in one tab.

Open the app — it’s free and private.