Performance

The Switch's Tegra X1 is a 2015-era mobile chip. Fast apps respect that.

UI rendering

• Flat fills beat gradients and shadows. CSS gradients and box-shadows are expensive on the software-composited UI path — flat colors render dramatically faster. (Brewser's own catalogue follows this rule.)
• Minimise layout thrash; batch DOM updates.

WebGL

• Batch draw calls; minimise state changes per frame.
• Compile shaders once at startup, never per frame.
• Prefer WebGL 1 techniques when you don't need WebGL 2 features — the compatibility surface is broadest there.
• Watch texture sizes; 4K textures are rarely worth it on a 720p handheld screen.

JavaScript

• V8's JIT is active on Brewser, so hot loops optimise well — but avoid allocation storms in your frame loop (object pooling pays off).
• Defer heavy work out of the boot path so click-to-play feels instant.