Near-native speed
WASM is an ahead-of-time compilation target with a linear memory model — no garbage-collection pauses, no dynamic-type overhead. Tight numeric loops run within a whisker of native code, with SIMD when the math wants it.
Demo 01 · raw number-crunching
Fractal explorer
Every pixel is an escape-time iteration over 64-bit complex numbers — up to fifteen hundred rounds of multiply-add per point, re-run as you move. Drag to pan, scroll to dive; the HUD shows real render times. Try the Burning Ship — the tiny ships along its antenna hide the deepest structure.
you've reached the edge of 64-bit floating point — ~10¹³× zoom
Demo 02 · sandboxed, not slow
Fluid dynamics
A Navier–Stokes solver — the equations behind smoke, ink and weather — integrated in real time on thirty-six thousand cells, every frame, inside the browser sandbox. Drag through it to stir.
drag to stir
What is it
A fourth language for the web
WebAssembly (WASM) is a compact binary instruction format — a portable compilation
target that runs alongside JavaScript in every modern browser. Code written in
Rust, C, C++, Go, Zig and dozens of other languages compiles down to a small
.wasm binary that the browser turns into machine code.
It isn't a plugin and it isn't a sandbox bolted onto the side of the web. It is a W3C standard, shipped everywhere, designed from the first byte for speed, safety and portability.
(module
(func $step (param $dt f32)
(local $i i32)
;; tight, typed, predictable —
;; this is what the browser JITs
;; into raw machine code
...)
(export "step" (func $step))
(memory (export "memory") 17))Sandboxed by design
Every module runs inside the browser's security sandbox with access to nothing but the memory it owns and the functions you hand it. Native-class compute, web-class safety.
Language-agnostic
One binary format, any source language. This site is Rust, but the same
.wasm could come from C++, Go, Zig or C# — and JavaScript calls it
all the same way.
Under the hood
Compiled before it finishes downloading
Browsers compile WebAssembly while it streams over the network — by the time the last byte arrives, the module is ready to run. No parse, no warm-up, no interpreter tier. These numbers are live from your visit:
—
wasm payload, over the wire
—
fetch + compile + instantiate
3
simulations in that one binary
Why it matters
Ship compute, not infrastructure
Workloads like the ones on this page used to mean native apps or a rack of servers rendering frames on someone else's machine. WebAssembly moves the compute to the edge of all edges — the visitor's own device — with nothing to install, nothing to containerize, and a security model the browser has spent twenty-five years hardening.
The entire engine behind this site is a single small binary, cached like any other asset and started in microseconds. It runs the same on a phone, a laptop, and the Raspberry Pi cluster serving it to you.