Solid

SolidJS delivers fine-grained reactivity and smaller bundles by compiling to surgical DOM updates. It looks like React (JSX, components, hooks-like primitives) but compiles down to direct DOM updates. No diffing, no reconciliation, no wasted renders.

MIT licensed. The framework consistently tops JavaScript framework benchmarks. Bundle sizes start around 7KB gzipped. It uses signals for reactivity: when a value changes, only the exact DOM node that uses it updates. Nothing else re-renders.

SolidJS itself is fully free. The pricing page is for SolidStart (their meta-framework, like Next.js is to React) and SolidCloud, but SolidJS the library costs nothing. The ecosystem is smaller than React's. Fewer component libraries, fewer tutorials, fewer Stack Overflow answers. But it's growing steadily with an active Discord and an enthusiastic community.

The catch: you're betting on a smaller ecosystem. Hiring Solid developers is harder than hiring React developers. Some React patterns don't translate (early returns in components break reactivity, destructuring props loses tracking). The mental model is subtly different even though the syntax looks familiar.