**WARNING: This is the documentation for `razzle@next` (Webpack 4).**  
[Go here for for razzle@0.8.x (stable) docs (Webpack 3)](https://github.com/jaredpalmer/razzle/tree/master).

![repo-banner](https://user-images.githubusercontent.com/4060187/28923990-050a32d4-782e-11e7-9da7-574ce5a8b455.png)

[![CircleCI](https://circleci.com/gh/jaredpalmer/razzle/tree/master.svg?style=shield)](https://circleci.com/gh/jaredpalmer/razzle/tree/master) ![Razzle-status](https://david-dm.org/jaredpalmer/razzle.svg?path=packages/razzle) [![npm version](https://badge.fury.io/js/razzle.svg)](https://badge.fury.io/js/razzle)

Universal JavaScript applications are tough to setup. Either you buy into a framework like [Next.js](https://github.com/zeit/next.js) or [react-server](https://github.com/redfin/react-server), fork a boilerplate, or set things up yourself. Aiming to fill this void, Razzle is a tool that abstracts all complex configuration needed for SSR into a single dependency--giving you the awesome developer experience of [create-react-app](https://github.com/facebookincubator/create-react-app), but then leaving the rest of your app's architectural decisions about frameworks, routing, and data fetching up to you. With this approach, Razzle not only works with React, but also Reason, Elm, Vue, Angular, and most importantly......whatever comes next.

**Razzle comes with the "battery-pack included"**:

* :fire: Universal Hot Module Replacement, so both the client and server update whenever you make edits. No annoying restarts necessary
* Comes with your favorite ES6 JavaScript goodies (through `babel-preset-razzle`)
* Comes with the same CSS setup as [create-react-app](https://github.com/facebookincubator/create-react-app)
* Works with [React](https://github.com/facebook/react), [Preact](https://github.com/developit/preact), [Elm](http://elm-lang.org/), [Reason-React](https://github.com/jaredpalmer/razzle/tree/master/examples/with-reason-react), [Inferno](https://github.com/infernojs), and [Rax](https://github.com/alibaba/rax) as well as [Angular](https://github.com/angular/angular) and [Vue](https://github.com/vuejs/vue) if that's your thing
* Escape hatches for customization via `.babelrc` and `razzle.config.js`
* [Jest](https://github.com/facebook/jest) test runner setup with sensible defaults via `razzle test`

## Quick Start

[![Greenkeeper badge](https://badges.greenkeeper.io/jaredpalmer/razzle.svg)](https://greenkeeper.io/)

```bash
npm install -g create-razzle-app

create-razzle-app my-app
cd my-app
npm start
```

Then open http://localhost:3000/ to see your app. Your console should look like this:

<img src="https://cloud.githubusercontent.com/assets/4060187/26324663/b31788c4-3f01-11e7-8e6f-ffa48533af54.png" width="500px" alt="Razzle Development Mode"/>

**That's it**. You don't need to worry about setting up multiple webpack configs or other build tools. Just start editing `src/App.js` and go!

Below is a list of commands you will probably find useful.

### `npm start` or `yarn start`

Runs the project in development mode.  
You can view your application at `http://localhost:3000`

The page will reload if you make edits.

### `npm run build` or `yarn build`

Builds the app for production to the build folder.

The build is minified and the filenames include the hashes.
Your app is ready to be deployed!

### `npm run start:prod` or `yarn start:prod`

Runs the compiled app in production.

You can again view your application at `http://localhost:3000`

### `npm test` or `yarn test`

Runs the test watcher (Jest) in an interactive mode.
By default, runs tests related to files changed since the last commit.

### `npm start -- --inspect` or `yarn start -- --inspect`

To debug the node server, you can use `razzle start --inspect`. This will start the node server and enable the inspector agent. For more information, see [this](https://nodejs.org/en/docs/inspector/).

### `npm start -- --inspect-brk` or `yarn start -- --inspect-brk`

To debug the node server, you can use `razzle start --inspect-brk`. This will start the node server, enable the inspector agent and Break before user code starts. For more information, see [this](https://nodejs.org/en/docs/inspector/).

### `rs`

If your application is running, and you need to manually restart your server, you do not need to completely kill and rebundle your application. Instead you can just type `rs` and press enter in terminal.

## <img src="https://user-images.githubusercontent.com/4060187/37915268-209644d0-30e7-11e8-8ef7-086b529ede8c.png" width="500px" alt="Razzle Hot Restart"/>

<!-- START doctoc generated TOC please keep comment here to allow auto update -->

<!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE -->

**Table of Contents**

* [Customization](#customization)
  * [Extending Babel Config](#extending-babel-config)
  * [Extending Webpack](#extending-webpack)
  * [Environment Variables](#environment-variables)
  * [Adding Temporary Environment Variables In Your Shell](#adding-temporary-environment-variables-in-your-shell)
    * [Windows (cmd.exe)](#windows-cmdexe)
    * [Linux, macOS (Bash)](#linux-macos-bash)
  * [Adding Environment Variables In `.env`](#adding-environment-variables-in-env)
    * [What other `.env` files are can be used?](#what-other-env-files-are-can-be-used)
* [How Razzle works (the secret sauce)](#how-razzle-works-the-secret-sauce)
* [Inspiration](#inspiration)
  * [Author](#author)
* [Contributors](#contributors)

<!-- END doctoc generated TOC please keep comment here to allow auto update -->

## Customization

### Customizing Babel Config

Razzle comes with most of ES6 stuff you need. However, if you want to add your own babel transformations, just add a `.babelrc` file to the root of your project.

```js
{
  "presets": [
    "razzle/babel", // NEEDED
    "stage-0"
   ],
   "plugins": [
     // additional plugins
   ]
}
```

A word of advice: the `.babelrc` file will replace the internal razzle babelrc template. You must include at the very minimum the default razzle/babel preset.

### Extending Webpack

You can also extend the underlying webpack config. Create a file called `razzle.config.js` in your project's root.

```js
// razzle.config.js

module.exports = {
  modify: (config, { target, dev }, webpack) => {
    // do something to config

    return config;
  },
};
```

A word of advice: `razzle.config.js` is an escape hatch. However, since it's just JavaScript, you can and should publish your `modify` function to npm to make it reusable across your projects. For example, imagine you added some custom webpack loaders and published it as a package to npm as `my-razzle-modifictions`. You could then write your `razzle.config.js` like so:

```
// razzle.config.js
const modify = require('my-razzle-modifictions');

module.exports = {
  modify
}
```

Last but not least, if you find yourself needing a more customized setup, Razzle is _very_ forkable. There is one webpack configuration factory that is 300 lines of code, and 4 scripts (`build`, `start`, `test`, and `init`). The paths setup is shamelessly taken from [create-react-app](https://github.com/facebookincubator/create-react-app), and the rest of the code related to logging.

### Environment Variables

**The environment variables are embedded during the build time.** You can read them at runtime just because by default we export them with the `webpack.DefinePlugin`.

* `process.env.RAZZLE_PUBLIC_DIR`: Absolute path to the public directory in the server's filesystem.
* `process.env.RAZZLE_ASSETS_MANIFEST`: Path to a file containing compiled asset outputs
* `process.env.REACT_BUNDLE_PATH`: Relative path to where React will be bundled during development. Unless you are modifying the output path of your webpack config, you can safely ignore this. This path is used by `react-error-overlay` and webpack to power up the fancy runtime error iframe. For example, if you are using common chunks and an extra entry to create a vendor bundle with stuff like react, react-dom, react-router, etc. called `vendor.js`, and you've changed webpack's output to `[name].js` in development, you'd want to set this environment variable to `/static/js/vendor.js`. If you do not make this change, nothing bad will happen, you will simply not get the cool error overlay when there are runtime errors. You'll just see them in the console. Note: This does not impact production bundling.
* `process.env.VERBOSE`: default is false, setting this to true will not clear the console when you make edits in development (useful for debugging).
* `process.env.PORT`: The `BUILD_TARGET=server` build listens on this port for all NODE_ENVs. default is `3000`
* `process.env.HOST`: The IP address that the server will bind to. default is `0.0.0.0`, for INADDR_ANY
* `process.env.NODE_ENV`: `'development'` or `'production'`
* `process.env.BUILD_TARGET`: either `'client'` or `'server'`
* `process.env.PUBLIC_PATH`: Only in used in `razzle build`. You can alter the `webpack.config.output.publicPath` of the client assets (bundle, css, and images). This is useful if you plan to serve your assets from a CDN. Make sure to _include_ a trailing slash (e.g. `PUBLIC_PATH=https://cdn.example.com/`). If you are using React and altering the public path, make sure to also [include the `crossorigin` attribute](https://reactjs.org/docs/installation.html#using-a-cdn) on your `<script>` tag in `src/server.js`.
* `process.env.CLIENT_PUBLIC_PATH`: The `NODE_ENV=development` build's `BUILD_TARGET=client` has a different `PUBLIC_PATH` than `BUILD_TARGET=server`. Default is `http://${process.env.HOST}:${process.env.PORT + 1}/`

You can create your own custom environment variables that will be inlined during the build. They must start
with `RAZZLE_`. Any other variables except the ones listed above will be ignored to avoid accidentally exposing a private key on the machine that could have the same name. Changing any environment variables will require you to restart the development server if it is running.

These environment variables will be defined for you on `process.env`. For example, having an environment variable named `RAZZLE_SECRET_CODE` will be exposed in your JS as `process.env.RAZZLE_SECRET_CODE`.

### Adding Temporary Environment Variables In Your Shell

Defining environment variables can vary between OSes. It’s also important to know that this manner is temporary for the
life of the shell session.

#### Windows (cmd.exe)

```cmd
set RAZZLE_SECRET_CODE=abcdef&&npm start
```

(Note: the lack of whitespace is intentional.)

#### Linux, macOS (Bash)

```bash
RAZZLE_SECRET_CODE=abcdef npm start
```

### Adding Environment Variables In `.env`

To define permanent environment variables, create a file called .env in the root of your project:

```
RAZZLE_SECRET_CODE=abcdef
```

#### What other `.env` files are can be used?

* `.env`: Default.
* `.env.local`: Local overrides. **This file is loaded for all environments except test.**
* `.env.development`, `.env.test`, `.env.production`: Environment-specific settings.
* `.env.development.local`, `.env.test.local`, `.env.production.local`: Local overrides of environment-specific settings.

Files on the left have more priority than files on the right:

* `npm start`: `.env.development.local`, `.env.development`, `.env.local`, `.env`
* `npm run build`: `.env.production.local`, `.env.production`, `.env.local`, `.env`
* `npm test`: `.env.test.local`, `.env.test`, `.env` (note `.env.local` is missing)

These variables will act as the defaults if the machine does not explicitly set them.<br>
Please refer to the [dotenv documentation](https://github.com/motdotla/dotenv) for more details.

> Note: If you are defining environment variables for development, your CI and/or hosting platform will most likely need
> these defined as well. Consult their documentation how to do this. For example, see the documentation for [Travis CI](https://docs.travis-ci.com/user/environment-variables/) or [Heroku](https://devcenter.heroku.com/articles/config-vars).

## How Razzle works (the secret sauce)

**tl;dr**: 2 configs, 2 ports, 2 webpack instances, both watching and hot reloading the same filesystem, in parallel during development and a little `webpack.output.publicPath` magic.

In development mode (`razzle start`), Razzle bundles both your client and server code using two different webpack instances running with Hot Module Replacement in parallel. While your server is bundled and run on whatever port your specify in `src/index.js` (`3000` is the default), the client bundle (i.e. entry point at `src/client.js`) is served via `webpack-dev-server` on a different port (`3001` by default) with its `publicPath` explicitly set to `localhost:3001` (and not `/` like many other setups do). Then the server's html template just points to the absolute url of the client JS: `localhost:3001/static/js/client.js`. Since both webpack instances watch the same files, whenever you make edits, they hot reload at _exactly_ the same time. Best of all, because they use the same code, the same webpack loaders, and the same babel transformations, you never run into a React checksum mismatch error.

## Inspiration

* [palmerhq/backpack](https://github.com/palmerhq/backpack)
* [nytimes/kyt](https://github.com/nytimes/kyt)
* [facebookincubator/create-react-app](https://github.com/facebookincubator/create-react-app)
* [humblespark/sambell](https://github.com/humblespark/sambell)
* [zeit/next.js](https://github.com/zeit/next.js)

#### Author

* [Jared Palmer](https://twitter.com/jaredpalmer)

---

MIT License

## Contributors

Thanks goes to these wonderful people ([emoji key](https://github.com/kentcdodds/all-contributors#emoji-key)):

<!-- ALL-CONTRIBUTORS-LIST:START - Do not remove or modify this section -->

| [<img src="https://avatars2.githubusercontent.com/u/4060187?v=4" width="100px;"/><br /><sub>Jared Palmer</sub>](http://jaredpalmer.com)<br />[💬](#question-jaredpalmer 'Answering Questions') [💻](https://github.com/jaredpalmer/razzle/commits?author=jaredpalmer 'Code') [🎨](#design-jaredpalmer 'Design') [📖](https://github.com/jaredpalmer/razzle/commits?author=jaredpalmer 'Documentation') [💡](#example-jaredpalmer 'Examples') [🤔](#ideas-jaredpalmer 'Ideas, Planning, & Feedback') [👀](#review-jaredpalmer 'Reviewed Pull Requests') [⚠️](https://github.com/jaredpalmer/razzle/commits?author=jaredpalmer 'Tests') [🔧](#tool-jaredpalmer 'Tools') | [<img src="https://avatars3.githubusercontent.com/u/1415847?v=4" width="100px;"/><br /><sub>Jari Zwarts</sub>](https://jari.io)<br />[💬](#question-jariz 'Answering Questions') [💻](https://github.com/jaredpalmer/razzle/commits?author=jariz 'Code') [🤔](#ideas-jariz 'Ideas, Planning, & Feedback') [🔌](#plugin-jariz 'Plugin/utility libraries') [👀](#review-jariz 'Reviewed Pull Requests') | [<img src="https://avatars0.githubusercontent.com/u/810438?v=4" width="100px;"/><br /><sub>Dan Abramov</sub>](http://twitter.com/dan_abramov)<br />[💻](https://github.com/jaredpalmer/razzle/commits?author=gaearon 'Code') [🤔](#ideas-gaearon 'Ideas, Planning, & Feedback') | [<img src="https://avatars0.githubusercontent.com/u/15182?v=4" width="100px;"/><br /><sub>Eric Clemmons</sub>](http://ericclemmons.github.com/)<br />[💻](https://github.com/jaredpalmer/razzle/commits?author=ericclemmons 'Code') [🤔](#ideas-ericclemmons 'Ideas, Planning, & Feedback') |
| : : | :---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------: | :-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------: | :-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------: |


<!-- ALL-CONTRIBUTORS-LIST:END -->

This project follows the [all-contributors](https://github.com/kentcdodds/all-contributors) specification. Contributions of any kind welcome!
