SolidJS vs React: Reactivity Models and Performance Compared

Overview

SolidJS and React both use JSX and a component-based architecture, making them look similar on the surface. The difference is fundamental: React re-renders entire component subtrees via a virtual DOM, while SolidJS uses fine-grained signals that update only the specific DOM nodes that changed. This architectural distinction has profound implications for performance, bundle size, and how developers think about state.

React dominates the frontend ecosystem with the largest community, the most mature tooling, and an enormous hiring pool. SolidJS is a newer challenger that consistently outperforms React in benchmarks while offering a surprisingly familiar developer experience for React engineers.

Key Technical Differences

The core difference is the reactivity model. In React, when state changes, the component function re-executes, produces a new virtual DOM tree, and React diffs it against the previous tree to determine minimal DOM updates. In SolidJS, component functions run exactly once. Signals — reactive primitives created with createSignal — track their dependencies automatically, and when a signal value changes, only the specific expression that reads it re-evaluates.

This means SolidJS does not need useMemo, useCallback, or React.memo to avoid unnecessary work. There are no stale closure bugs because closures do not re-execute. SolidJS components are essentially setup functions: they wire up reactive bindings once and those bindings manage their own updates.

The trade-off is ecosystem maturity. React's component libraries (Material UI, Radix, shadcn/ui), state managers (Zustand, Jotai, Redux), and meta-frameworks (Next.js, Remix) represent thousands of person-years of development. SolidJS has SolidStart for SSR and a growing library ecosystem, but it cannot match React's breadth today.

Performance & Scale

In the JS Framework Benchmark, SolidJS consistently ranks among the fastest frameworks, often matching vanilla JavaScript performance. React is fast enough for most applications, but its VDOM diffing adds a baseline cost that becomes measurable in complex UIs with frequent updates — large data tables, real-time charts, or collaborative editors. SolidJS's 7 KB gzipped core also makes it a strong choice for embedded widgets or performance-sensitive mobile web experiences.

When to Choose Each

Choose SolidJS when raw performance and small bundle size are non-negotiable requirements, or when you are starting a greenfield project and your team is willing to invest in a smaller ecosystem. It is particularly compelling for performance-critical applications like trading dashboards or interactive data visualizations.

Choose React when you need the largest ecosystem, the easiest hiring, and battle-tested meta-frameworks. React's community momentum, corporate backing, and continuous innovation (Server Components, the React compiler) make it the pragmatic default for most production applications.

Bottom Line

SolidJS is what React would look like if it were redesigned today with fine-grained reactivity and no VDOM. It is faster, smaller, and simpler in many ways — but React's ecosystem and community are an order of magnitude larger. Choose SolidJS for performance; choose React for ecosystem and hiring.