Preact definition

What is Preact?

Preact is a fast and lightweight alternative to React, a popular JavaScript library for building user interfaces. Notably, Preact stands out due to its small footprint and high performance, making it ideal for quick browsing experiences. Unlike React, it can be used directly in the browser without any transpilation steps, reducing both download and execution times.

One of Preact's defining features is its focus on simplicity while offering a modern API for creating interactive user interfaces. It's designed with productivity in mind, providing developers more control over their code. Most importantly, Preact maintains compatibility with React components and tools, which facilitates an easy transition from React.

Preact aims to deliver efficiency and top-notch performance when building web applications without overwhelming the developer with unnecessary complexity.

Preact 11 was released on September 29, 2026, followed by 11.0.1 on October 8, 2026. The Preact team describes it as an incremental major upgrade over the Preact X line rather than a rewrite, bundling breaking changes that had accumulated for years. The points that matter to most projects: distribution is ESM only, so the .module.js, CommonJS, and UMD bundles are gone (a few preact/compat entry points such as preact/compat/server keep CommonJS wrappers), TypeScript 5.1 is the minimum for typed projects, and the supported browser floor moved to Chrome 71, Safari 12.1, Firefox 69, and Edge 79. Hydration 2.0 drops the Preact X rule that an async boundary had to return exactly one DOM node, and coordinates with streamed server output using stable comment markers.

Preact vs React: Understanding the Differences

While React is a popular choice for web app development, it has been critiqued as being slow due to its virtual DOM and large file size. This is where Preact steps in, offering a smaller and faster alternative. It's important to note that Preact does not aim to replicate every feature of React. Instead, it prioritizes simplicity, performance, and closely following the DOM specification.

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Preact offers an additional advantage with its 'preact/compat' layer that ensures compatibility with existing React codebases. This allows developers to migrate from React to Preact without extensive rewrites or adjustments.

Preact 11 narrows the remaining gaps. Refs are forwarded by default, so a function component can accept ref as an ordinary prop and forwardRef is no longer needed for that case, though under preact/compat refs are still not forwarded to class components, matching React. createPortal is available from preact itself and remains exported from preact/compat, so existing imports keep working. Hook arguments are compared with Object.is, which aligns with React and makes NaN usable as a state value or a dependency. On the compat side, use(), useEffectEvent(), the optional getServerSnapshot argument for useSyncExternalStore(), and the context argument for Children.map() and Children.forEach() are all available, while automatic px suffixing of numeric style values and defaultProps support moved out of core and into preact/compat. Preact documents its compatibility against the current and previous major React releases.

Preact also simplifies event handling, adhering closely to standard browser behaviors rather than trying to abstract them away. The result? A leaner library that addresses performance bottlenecks while still maintaining much of the familiarity and power of React.

Key Benefits of Using Preact

Preact provides several key benefits that make it an attractive choice for developers. First and foremost, its small size and high speed lead to faster loading times, leading to a more responsive user experience. This makes Preact particularly beneficial for web applications where performance is critical.

A prime aspect of Preact's appeal is its ability to integrate well with other libraries. This flexibility allows developers to leverage existing tools and frameworks in their projects, thereby enhancing productivity.

Perhaps the most significant benefit comes from Preact's compatibility with React. Thanks to this feature, transitioning from React to Preact can be a smooth process without major code rewrite or adjustment. Furthermore, the simpler API and less abstraction in event handling make working with Preact a straightforward affair.

Integrating Preact with Other Tools

Preact's flexibility extends to its compatibility with various other tools and frameworks. This adaptability opens up a world of possibilities for developers, making it possible to mix and match tools based on specific project requirements.

A key example is pairing Preact with Sanity, the AI Content Operating System that replaces headless CMSes, DXPs, and homegrown content systems. A Preact app queries the Content Lake over the hosted API, and because a GROQ query returns only the fields it projects, the component receives the shape it renders rather than a document it has to pick apart. There is no over-fetching, no N+1 round trip, and no resolver layer to maintain, which keeps the payload small on a library chosen for being small. That is structured content serving one channel from a single source of truth.

Whether you're looking at frontend frameworks like Next.js or a content backend like Sanity, Preact plays well with others and enhances the overall development experience. It simplifies the process of building powerful web applications while harnessing the strengths of various other technologies in your stack.

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Last updated: October 10, 2026