This page is an overview of the React documentation and related resources.
**React** is a JavaScript library for building user interfaces. Learn what React is all about on [our homepage](/) or [in the tutorial](/tutorial/tutorial.html).
React has been designed from the start for gradual adoption, and you can use as little or as much React as you need. Whether you want to get a taste of React, add some interactivity to a simple HTML page, or start a complex React-powered app, the links in this section will help you get started.
If you're interested in playing around with React, you can use an online code playground. Try a Hello World template on [CodePen](codepen://hello-world) or [CodeSandbox](https://codesandbox.io/s/new). If you prefer to use your own text editor, you can also [download this HTML file](https://raw.githubusercontent.com/reactjs/reactjs.org/master/static/html/single-file-example.html), edit it, and open it from the local filesystem in your browser. It does a slow runtime code transformation, so we'd only recommend using this for simple demos.
### Add React to a Website
You can [add React to an HTML page in one minute](/docs/add-react-to-a-website.html). You can then either gradually expand its presence, or keep it contained to a few dynamic widgets.
### Create a New React App
When starting a React project, [a simple HTML page with script tags](/docs/add-react-to-a-website.html) might still be the best option.
As your application grows, you might want to consider a more integrated setup. There are [several recommended solutions](/docs/create-a-new-react-app.html) for creating JavaScript applications with React. Each of them can work with little to no configuration and lets you take full advantage of the rich React ecosystem.
## Learn React
People come to React from different backgrounds and with different learning styles. Whether you prefer a more theoretical or a more practical approach, we hope you'll find something useful in this section.
The React documentation assumes some familiarity with programming in the JavaScript language. You don't have to be an expert, but it's harder to learn both React and JavaScript at the same time.
We recommend going through [this JavaScript tutorial](https://developer.mozilla.org/en-US/docs/Web/JavaScript/A_re-introduction_to_JavaScript) to check your knowledge level. It will likely take you between 30 minutes and an hour but will help you feel more confident learning React.
>Whenever you get confused by something in JavaScript, [MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript) and [javascript.info](http://javascript.info/) are great websites to check. There are also [community support forums](/community/support.html) where you can ask for help.
If you prefer to **learn by doing,** check out our [practical tutorial](/tutorial/tutorial.html). In this tutorial, we build a tic-tac-toe game in React. You might be tempted to skip it because you're not building games -- but give it a chance. The techniques you'll learn in the tutorial are fundamental to building *any* React apps, and mastering it will give you a much deeper understanding.
If you prefer to **learn concepts step by step,** our [guide to main concepts](/docs/hello-world.html) is the best place to start. Every next chapter in it builds on the knowledge introduced in the previous chapters so you won't miss anything as you go along.
Many React users credit reading [Thinking in React](/docs/thinking-in-react.html) as the moment React finally "clicked" for them. It's probably the oldest React walkthrough that was ever written but it's still just as relevant.
### Recommended Courses
Sometimes people find third-party books and video courses more helpful than the official documentation. We maintain [a list of commonly recommended resources](/community/courses.html), some of which are free.
### Advanced Concepts
Once you're comfortable with the [main concepts](#main-concepts) and played with React a little bit, you might be interested in more advanced topics. This section will introduce you to the powerful, but less commonly used React features like [context](/docs/context.html) and [refs](/docs/refs-and-the-dom.html).
### API Reference
This documentation section is useful when you want to learn more details about a particular React API. For example, [`React.Component` API reference](/docs/react-component.html) can provide you with details on how `setState()` works, and what different lifecycle hooks are useful for.
The [glossary](/docs/glossary.html) contains an overview of the most common terms you'll see in the React documentation. There is also a FAQ section dedicated to short questions and answers about common topics, including [making AJAX requests](/docs/faq-ajax.html), [component state](/docs/faq-state.html), and [file structure](/docs/faq-structure.html).
The [React blog](/blog/) is the official source for the updates from the React team. Anything important, including release notes or deprecation notices, will be posted there first.
You can also follow the [@reactjs account](https://twitter.com/reactjs) on Twitter, but you won't miss anything essential if you only read the blog.
Not every React release deserves its own blog post, but you can find a detailed changelog for every release [in the `CHANGELOG.md` file in the React repository](https://github.com/facebook/react/blob/master/CHANGELOG.md), as well as on the [Releases](https://github.com/facebook/react) page.
## Versioned Documentation
This documentation always reflects the latest stable version of React. Since React 16, you can find older versions of the documentation [on a separate page](/versions). Note that documentation for past versions is snapshotted at the time of the release, and isn't being continuously updated.
## Something Missing?
If something is missing in the documentation or if you found some part confusing, please [file an issue for the documentation repository](https://github.com/reactjs/reactjs.org/issues/new) with your suggestions for improvement, or tweet at the [@reactjs account](https://twitter.com/reactjs). We love hearing from you!
