webpack-dev-server

Use webpack with a development server that provides live reloading. This should be used for development only.

It uses webpack-dev-middleware under the hood, which provides fast in-memory access to the webpack assets.

Table of Contents

• Getting Started
• Usage
  • With the CLI
  • With NPM Scripts
  • With the API
  • With TypeScript
  • The Result
• Browser Support
• Support
• Contributing
• Attribution
• License

Getting Started

First things first, install the module:

npm install webpack-dev-server --save-dev

or

yarn add -D webpack-dev-server

or

pnpm add -D webpack-dev-server

Note: While you can install and run webpack-dev-server globally, we recommend installing it locally. webpack-dev-server will always use a local installation over a global one.

Usage

There are two main, recommended methods of using the module:

With the CLI

The easiest way to use it is with the webpack CLI. In the directory where your webpack.config.js is, run:

npx webpack serve

Following options are available with webpack serve:

Usage: webpack serve|server|s [entries...] [options]

Run the webpack dev server.

Options:
  -c, --config <value...>                   Provide path to a webpack configuration file e.g. ./webpack.config.js.
  --config-name <value...>                  Name of the configuration to use.
  -m, --merge                               Merge two or more configurations using 'webpack-merge'.
  --env <value...>                          Environment passed to the configuration when it is a function.
  --node-env <value>                        Sets process.env.NODE_ENV to the specified value.
  --progress [value]                        Print compilation progress during build.
  -j, --json [value]                        Prints result as JSON or store it in a file.
  --entry <value...>                        The entry point(s) of your application e.g. ./src/main.js.
  -o, --output-path <value>                 Output location of the file generated by webpack e.g. ./dist/.
  -t, --target <value>                      Sets the build target e.g. node.
  -d, --devtool <value>                     Determine source maps to use.
  --no-devtool                              Do not generate source maps.
  --mode <value>                            Defines the mode to pass to webpack.
  --name <value>                            Name of the configuration. Used when loading multiple configurations.
  --stats [value]                           It instructs webpack on how to treat the stats e.g. verbose.
  --no-stats                                Disable stats output.
  --watch-options-stdin                     Stop watching when stdin stream has ended.
  --no-watch-options-stdin                  Do not stop watching when stdin stream has ended.
  --allowed-hosts <value...>                Allows to enumerate the hosts from which access to the dev server are allowed (useful when you are proxying dev server, by default is 'auto').
  --allowed-hosts-reset                     Clear all items provided in 'allowedHosts' configuration. Allows to enumerate the hosts from which access to the dev server are allowed (useful when
                                            you are proxying dev server, by default is 'auto').
  --bonjour                                 Allows to broadcasts dev server via ZeroConf networking on start.
  --no-bonjour                              Disallows to broadcasts dev server via ZeroConf networking on start.
  --no-client                               Disables client script.
  --client-logging <value>                  Allows to set log level in the browser.
  --client-overlay                          Enables a full-screen overlay in the browser when there are compiler errors or warnings.
  --no-client-overlay                       Disables the full-screen overlay in the browser when there are compiler errors or warnings.
  --client-overlay-errors                   Enables a full-screen overlay in the browser when there are compiler errors.
  --no-client-overlay-errors                Disables the full-screen overlay in the browser when there are compiler errors.
  --client-overlay-warnings                 Enables a full-screen overlay in the browser when there are compiler warnings.
  --no-client-overlay-warnings              Disables the full-screen overlay in the browser when there are compiler warnings.
  --client-progress                         Prints compilation progress in percentage in the browser.
  --no-client-progress                      Does not print compilation progress in percentage in the browser.
  --client-reconnect [value]                Tells dev-server the number of times it should try to reconnect the client.
  --no-client-reconnect                     Tells dev-server to not to try to reconnect the client.
  --client-web-socket-transport <value>     Allows to set custom web socket transport to communicate with dev server.
  --client-web-socket-url <value>           Allows to specify URL to web socket server (useful when you're proxying dev server and client script does not always know where to connect to).
  --client-web-socket-url-hostname <value>  Tells clients connected to devServer to use the provided hostname.
  --client-web-socket-url-password <value>  Tells clients connected to devServer to use the provided password to authenticate.
  --client-web-socket-url-pathname <value>  Tells clients connected to devServer to use the provided path to connect.
  --client-web-socket-url-port <value>      Tells clients connected to devServer to use the provided port.
  --client-web-socket-url-protocol <value>  Tells clients connected to devServer to use the provided protocol.
  --client-web-socket-url-username <value>  Tells clients connected to devServer to use the provided username to authenticate.
  --compress                                Enables gzip compression for everything served.
  --no-compress                             Disables gzip compression for everything served.
  --history-api-fallback                    Allows to proxy requests through a specified index page (by default 'index.html'), useful for Single Page Applications that utilise the HTML5
                                            History API.
  --no-history-api-fallback                 Disallows to proxy requests through a specified index page.
  --host <value>                            Allows to specify a hostname to use.
  --hot [value]                             Enables Hot Module Replacement.
  --no-hot                                  Disables Hot Module Replacement.
  --http2                                   Allows to serve over HTTP/2 using SPDY. Deprecated, use the `server` option.
  --no-http2                                Does not serve over HTTP/2 using SPDY.
  --https                                   Allows to configure the server's listening socket for TLS (by default, dev server will be served over HTTP). Deprecated, use the `server` option.
  --no-https                                Disallows to configure the server's listening socket for TLS (by default, dev server will be served over HTTP).
  --https-ca <value...>                     Path to an SSL CA certificate or content of an SSL CA certificate. Deprecated, use the `server.options.ca` option.
  --https-ca-reset                          Clear all items provided in 'https.ca' configuration. Path to an SSL CA certificate or content of an SSL CA certificate. Deprecated, use the
                                            `server.options.ca` option.
  --https-cacert <value...>                 Path to an SSL CA certificate or content of an SSL CA certificate. Deprecated, use the `server.options.ca` option.
  --https-cacert-reset                      Clear all items provided in 'https.cacert' configuration. Path to an SSL CA certificate or content of an SSL CA certificate. Deprecated, use the
                                            `server.options.ca` option.
  --https-cert <value...>                   Path to an SSL certificate or content of an SSL certificate. Deprecated, use the `server.options.cert` option.
  --https-cert-reset                        Clear all items provided in 'https.cert' configuration. Path to an SSL certificate or content of an SSL certificate. Deprecated, use the
                                            `server.options.cert` option.
  --https-crl <value...>                    Path to PEM formatted CRLs (Certificate Revocation Lists) or content of PEM formatted CRLs (Certificate Revocation Lists). Deprecated, use the
                                            `server.options.crl` option.
  --https-crl-reset                         Clear all items provided in 'https.crl' configuration. Path to PEM formatted CRLs (Certificate Revocation Lists) or content of PEM formatted CRLs
                                            (Certificate Revocation Lists). Deprecated, use the `server.options.crl` option.
  --https-key <value...>                    Path to an SSL key or content of an SSL key. Deprecated, use the `server.options.key` option.
  --https-key-reset                         Clear all items provided in 'https.key' configuration. Path to an SSL key or content of an SSL key. Deprecated, use the `server.options.key` option.
  --https-passphrase <value>                Passphrase for a pfx file. Deprecated, use the `server.options.passphrase` option.
  --https-pfx <value...>                    Path to an SSL pfx file or content of an SSL pfx file. Deprecated, use the `server.options.pfx` option.
  --https-pfx-reset                         Clear all items provided in 'https.pfx' configuration. Path to an SSL pfx file or content of an SSL pfx file. Deprecated, use the
                                            `server.options.pfx` option.
  --https-request-cert                      Request for an SSL certificate. Deprecated, use the `server.options.requestCert` option.
  --no-https-request-cert                   Does not request for an SSL certificate.
  --ipc [value]                             Listen to a unix socket.
  --live-reload                             Enables reload/refresh the page(s) when file changes are detected (enabled by default).
  --no-live-reload                          Disables reload/refresh the page(s) when file changes are detected (enabled by default)
  --magic-html                              Tells dev-server whether to enable magic HTML routes (routes corresponding to your webpack output, for example '/main' for 'main.js').
  --no-magic-html                           Disables magic HTML routes (routes corresponding to your webpack output, for example '/main' for 'main.js').
  --open [value...]                         Allows to configure dev server to open the browser(s) and page(s) after server had been started (set it to true to open your default browser).
  --no-open                                 Does not open the default browser.
  --open-app <value...>                     Open specified browser. Deprecated: please use '--open-app-name'.
  --open-app-name <value...>                Open specified browser.
  --open-app-name-reset                     Clear all items provided in 'open.app.name' configuration. Open specified browser.
  --open-reset                              Clear all items provided in 'open' configuration. Allows to configure dev server to open the browser(s) and page(s) after server had been started
                                            (set it to true to open your default browser).
  --open-target <value...>                  Opens specified page in browser.
  --open-target-reset                       Clear all items provided in 'open.target' configuration. Opens specified page in browser.
  --port <value>                            Allows to specify a port to use.
  --server-options-ca <value...>            Path to an SSL CA certificate or content of an SSL CA certificate.
  --server-options-ca-reset                 Clear all items provided in 'server.options.ca' configuration. Path to an SSL CA certificate or content of an SSL CA certificate.
  --server-options-cacert <value...>        Path to an SSL CA certificate or content of an SSL CA certificate. Deprecated, use the `server.options.ca` option.
  --server-options-cacert-reset             Clear all items provided in 'server.options.cacert' configuration. Path to an SSL CA certificate or content of an SSL CA certificate. Deprecated,
                                            use the `server.options.ca` option.
  --server-options-cert <value...>          Path to an SSL certificate or content of an SSL certificate.
  --server-options-cert-reset               Clear all items provided in 'server.options.cert' configuration. Path to an SSL certificate or content of an SSL certificate.
  --server-options-crl <value...>           Path to PEM formatted CRLs (Certificate Revocation Lists) or content of PEM formatted CRLs (Certificate Revocation Lists).
  --server-options-crl-reset                Clear all items provided in 'server.options.crl' configuration. Path to PEM formatted CRLs (Certificate Revocation Lists) or content of PEM
                                            formatted CRLs (Certificate Revocation Lists).
  --server-options-key <value...>           Path to an SSL key or content of an SSL key.
  --server-options-key-reset                Clear all items provided in 'server.options.key' configuration. Path to an SSL key or content of an SSL key.
  --server-options-passphrase <value>       Passphrase for a pfx file.
  --server-options-pfx <value...>           Path to an SSL pfx file or content of an SSL pfx file.
  --server-options-pfx-reset                Clear all items provided in 'server.options.pfx' configuration. Path to an SSL pfx file or content of an SSL pfx file.
  --server-options-request-cert             Request for an SSL certificate.
  --no-server-options-request-cert          Negative 'server-options-request-cert' option.
  --server-type <value>                     Allows to set server and options (by default 'http').
  --static [value...]                       Allows to configure options for serving static files from directory (by default 'public' directory).
  --no-static                               Negative 'static' option.
  --static-directory <value...>             Directory for static contents.
  --static-public-path <value...>           The static files will be available in the browser under this public path.
  --static-public-path-reset                Clear all items provided in 'static.publicPath' configuration. The static files will be available in the browser under this public path.
  --static-reset                            Clear all items provided in 'static' configuration. Allows to configure options for serving static files from directory (by default 'public'
                                            directory).
  --static-serve-index                      Tells dev server to use serveIndex middleware when enabled.
  --no-static-serve-index                   Does not tell dev server to use serveIndex middleware.
  --static-watch                            Watches for files in static content directory.
  --no-static-watch                         Does not watch for files in static content directory.
  --watch-files <value...>                  Allows to configure list of globs/directories/files to watch for file changes.
  --watch-files-reset                       Clear all items provided in 'watchFiles' configuration. Allows to configure list of globs/directories/files to watch for file changes.
  --web-socket-server <value>               Deprecated: please use '--web-socket-server-type' option. Allows to set web socket server and options (by default 'ws').
  --no-web-socket-server                    Negative 'web-socket-server' option.
  --web-socket-server-type <value>          Allows to set web socket server and options (by default 'ws').

Global options:
  --color                                   Enable colors on console.
  --no-color                                Disable colors on console.
  -v, --version                             Output the version number of 'webpack', 'webpack-cli' and 'webpack-dev-server' and commands.
  -h, --help [verbose]                      Display help for commands and options.

To see list of all supported commands and options run 'webpack --help=verbose'.

Webpack documentation: https://webpack.js.org/.
CLI documentation: https://webpack.js.org/api/cli/.
Made with ♥ by the webpack team.

Note: For more information on above options explore this link.

With NPM Scripts

NPM package.json scripts are a convenient and useful means to run locally installed binaries without having to be concerned about their full paths. Simply define a script as such:

{
  "scripts": {
    "serve": "webpack serve"
  }
}

And run the following in your terminal/console:

npm run serve

NPM will automagically reference the binary in node_modules for you, and execute the file or command.

With the API

While it's recommended to run webpack-dev-server via the CLI, you may also choose to start a server via the API.

See the related API documentation for webpack-dev-server.

With TypeScript

If you use TypeScript in the webpack config, you'll need to properly type devServer property in order to avoid TS errors (e.g. 'devServer' does not exist in type 'Configuration'). For that use either:

/// <reference path="node_modules/webpack-dev-server/types/lib/Server.d.ts"/>
import type { Configuration } from "webpack";

// Your logic

Or you can import the type from webpack-dev-server, i.e.

import type { Configuration as DevServerConfiguration } from "webpack-dev-server";
import type { Configuration } from "webpack";

const devServer: DevServerConfiguration = {};
const config: Configuration = { devServer };

// module.exports
export default config;

The Result

Either method will start a server instance and begin listening for connections from localhost on port 8080.

webpack-dev-server is configured by default to support live-reload of files as you edit your assets while the server is running.

See the documentation for more use cases and options.

Browser Support

While webpack-dev-server transpiles the client (browser) scripts to an ES5 state, the project only officially supports the last two versions of major browsers. We simply don't have the resources to support every whacky browser out there.

If you find a bug with an obscure / old browser, we would actively welcome a Pull Request to resolve the bug.

Support

We do our best to keep issues in the repository focused on bugs, features, and needed modifications to the code for the module. Because of that, we ask users with general support, "how-to", or "why isn't this working" questions to try one of the other support channels that are available.

Your first-stop-shop for support for webpack-dev-server should be the excellent documentation for the module. If you see an opportunity for improvement of those docs, please head over to the webpack.js.org repo and open a pull request.

From there, we encourage users to visit the webpack Gitter chat and talk to the fine folks there. If your quest for answers comes up dry in chat, head over to StackOverflow and do a quick search or open a new question. Remember; It's always much easier to answer questions that include your webpack.config.js and relevant files!

If you're twitter-savvy you can tweet #webpack with your question and someone should be able to reach out and lend a hand.

If you have discovered a 🐛, have a feature suggestion, or would like to see a modification, please feel free to create an issue on Github. Note: The issue template isn't optional, so please be sure not to remove it, and please fill it out completely.

Contributing

We welcome your contributions! Please have a read of CONTRIBUTING.md for more information on how to get involved.

Attribution

This project is heavily inspired by peerigon/nof5.

License

MIT