Brunch: Config

Brunch uses configuration file brunch-config.js (or .coffee) to manage various aspects of your app.

  • paths — where to take files from and where to put generated ones
  • files — which files exactly should Brunch generate and how.
  • npm — NPM dependencies settings
  • plugins — individual plugin settings.

Less common options:

  • modules — specifies details of JS module implementation, such as wrapper, definition, autoRequire and nameCleaner.
  • conventions — defines which files are treated as assets and which ones are ignored in your app.
  • watcher — low-level configuration of the file watcher which empowers Brunch.
  • server — allows to describe custom web-servers instead of the built-in one.
  • notifications — configures the levels of notifications, their title, icon, etc.
  • sourceMaps, optimize — simple true/false options
  • hooks — allows to specify handlers for different moments of building cycle

You can see the config schema, and all the defaults, in the configBaseSchema of lib/utils/config-validate.js in the Brunch source code.


Simplest Brunch config looks like that. Just 6 lines of pure configuration:

module.exports = {
  files: {
    javascripts: {joinTo: 'app.js'},
    stylesheets: {joinTo: 'app.css'},

Each Brunch config is an executable script, so you can also execute arbitrary JS and import Node.js modules there.

Pattern matching

Internally, Brunch uses anymatch for pattern matching — it's a module to match strings against configurable strings, globs, regular expressions or functions. If you want to define specific file pattern, you can use:

  • String — path to your source files to be directly matched. You can use globs), so these strings may contain wildcard characters (*, ?, etc). Example:

    joinTo: {
      'app.css': 'path/to/*.css' // matches all CSS files
  • Regular expression — feel free to define a pattern using regular expression if you used to. Example:

    joinTo: {
      'app.js': /\.js$/ // matches all JavaScript files
  • Function — if you need especially specific pattern, you can define it using function that takes the string as an argument and returns a truthy or falsy value (like Array.filter function do). Example:

    joinTo: {
      // matches all JavaScript files with filenames longer that 3 characters
      'app.js': path => path.endsWith('.js') && path.length > 3
  • Array — an array of any number and mix of the above types. Example:

    joinTo: {
      'app.js': [
        'path/to/specific/file.js',   // include specific file
        'any/**/*.js',                // all files with .js extension
        /\.test\.js$/,                // all files with .test.js extension
        path => path.includes('tmp')  // contains `tmp` substring


Object: paths contains application paths to key directories. Paths are simple strings.

  • public key: path to build directory that would contain output.
  • watched key: list of all watched paths by brunch. Default: ['app', 'test', 'vendor']


paths: {
  public: '/user/www/deploy'

If you need to change the default directory for application's code, don't forget to add this directory to the watched field, like so:

paths: {
  watched: ['src']

Also, consider module.nameCleaner option, if you need to require your modules without prefixing with folder name.


(javascripts, stylesheets, templates; joinTos and order)

Required, object: files configures handling of application files: which compiler would be used on which file, what name should output file have etc. Any paths specified here must be listed in paths.watched as described above, for building.

  • <type>: javascripts, stylesheets or templates
    • joinTo: (required when no entryPoints was declared) describes how files will be compiled & joined together. Available formats:
      • 'outputFilePath' in order to have all source files compiled together to one
      • map of 'outputFilePath' (see Pattern matching section)
    • entryPoints: (optional) describes the entry points of an application. The specified file and all of its dependencies will then be joined into a single file (or if you have specified a mapping, into several files). Resembles joinTo but allows to included only required files. Because entryPoints is so similar to joinTo, it is better to choose only one of them in most cases. See the example below. Available formats:
      • 'entryFile.js': 'outputFilePath'
      • 'entryFile.js': map of 'outputFilePath' (see Pattern matching section)
    • order: (optional) defines compilation order. vendor files will be compiled before other ones even if they are not present here.
    • pluginHelpers: (optional) specify which output file (or array of files) plugins' include files concatenate into. Defaults to the output file that vendor files are being joined to, the first one with vendor in its name/path, or just the first output file listed in your joinTo object.

All files from vendor directory are by default concatenated before all files from app directory. So, vendor/scripts/jquery.js would be loaded before app/script.js even if order config is empty. Files from Bower packages are included by default before the vendor files.

Overall ordering is [before] -> [bower] -> [vendor] -> [everything else] -> [after]

Common example:

files: {
  javascripts: {
    joinTo: {
      'javascripts/app.js': /^app/,
      'javascripts/vendor.js': /^(?!app)/
   // or
   // entryPoints: {
   //   'entryPoints.js': {
   //     'javascripts/app.js': /^app/,
   //     'javascripts/vendor.js': /^(?!app)/
   //   }
   // }

  stylesheets: {
    joinTo: 'stylesheets/app.css'
  templates: {
    joinTo: 'javascripts/app.js'

A note on entry points

It is important to keep a few things in mind regarding entry points & their known limitations:

  • only the things you require will be included into an entryPoint bundle. This means non-app/non-npm dependencie won't be included. Also means only statically analyzable requires will work:
    • require('something') — :+1:
    • ['a', 'b', 'c'].forEach(dep => require(dep)) — :-1:
    • match('/', 'app/Home') (where app/Home gets translated into require('components/app/Home')) — :-1:
  • two entry points can't write to the same file

    javascripts: {
      entryPoints: {
        'app/initialize.js': 'javascripts/bundle.js',
        // INVALID
        'app/bookmarklet.js': 'javascripts/bundle.js'
  • all config.npm.globals will be included in every entry point and joinTo
  • entryPoints only work with javascript files. If you want to also include your templates, keep a joinTo for them


Object: configures NPM integration for front-end packages. Make sure you also declare the packages you depend on in your package.json dependencies section.

  • npm.enabled: Boolean: a toggle of whether the integration is enabled, defaults to true.
  • npm.globals: Object: a mapping from global name (as a key) to the corresponding module name (string) to expose.
  • npm.styles: Object: a mapping from package name (string) to an array of stylesheet paths (relative to package root) to be included into the build.
  • npm.static: Array: a list of javascript files from npm packages to be included as-is, without analyzing their dependencies or wrapping them into modules.
  • npm.aliases: Object: a mapping of files from an alias to a real package name. For example, if you are using exoskeleton fork of Backbone, setting this to {"backbone": "exoskeleton"} would load Exoskeleton when requiring backbone.


npm: {
  styles: {pikaday: ['css/pikaday.css']},
  globals: {Pikaday: 'pikaday'}


Object: Optional control to modify how plugins are loaded by default, as well as containing plugin-specific configuration.

  • off: Plugins that may be installed, but should not be run.
  • on: Forces listed plugins to be run, such as an optimizer even when the optimize flag is off.
  • only: Explicitly list the plugins to be used, ignoring any others that are installed.
  • npm: An array list of plugin names that will compile node_modules/. Defaults to []. (Note: for the time being, it works only with .js files)
  • Per-Plugin: Refer to each plugin's documentation for usage information.


plugins: {
  on: ['postcss-brunch'],
  off: ['jade-brunch', 'handlebars-brunch'],
  npm: ['babel-brunch'],
  autoReload: {enabled: true}


Object: conventions define tests, against which all file pathnames will be checked.

  • ignored key: matching pattern. Will check against files that should be ignored by brunch compiler, but are still watched by the watcher. For example, when you have common.styl file that you import in every stylus file, common.styl will be compiled on its own too which will result in duplicated code. When prefixing it with underscore (_common.styl) you are still able to import it in dependent files, but it won’t be compiled twice. The feature is very similar to Sass partials. By default, files and directories that start with underscore (_) will be ignored.
  • assets key: matching pattern. If test gives true, file won't be compiled and will be just moved to public directory instead.
  • vendor key: matching pattern. If test gives true, file won't be wrapped in module, if there are any.

Keep in mind that default brunch regexps, as you see, consider all vendor/ (etc.) directories as vendor (etc.) files. So, app/views/vendor/thing/file.js will be treated as vendor file.


conventions: {
  ignored: () => false, // override defaults for no ignored files
  assets: /files\//     // vendor/jquery/files/jq.img

You may find default values for ignored, assets and vendor fields in Brunch sources.


Object: consists of wrapper and definition subsettings.

modules.wrapper: String, Boolean or Function: a wrapper that will be wrapped around compiled-to-javascript code in non-vendor directories. Values:

  • commonjs (Default) — CommonJS wrapper.
  • amd — AMD r.js-like wrapper.
  • false — no wrapping. Files will be compiled as-is.
  • Function that takes path, data, and a boolean set to true if the file is in a vendor directory.

modules.definition: String, Boolean or Function a code that will be added on top of every generated JavaScript file. Values:

  • commonjs (Default) — CommonJS require definition.
  • amd, false — no definition.
  • Function that takes path and data


// Same as 'commonjs'.
modules: {
  wrapper: (path, data) => {
    return `
require.define({${path}: function(exports, require, module) {

modules.autoRequire: Object specifies requires to be automatically added at the end of joined file. The example below will require both 'app' and 'foo':

// Default behaviour.
modules: {
  autoRequire: {
    'javascripts/app.js': ['app', 'foo']

modules.nameCleaner: Function Allows you to set filterer function for module names, for example, change all 'app/file' to 'file'. Example:

// Default behaviour.
modules: {
  nameCleaner: path => path.replace(/^app\//, '')
// Add namespacing to a project.
const {name} = require('./package.json');
modules: {
  nameCleaner: path => path.replace(/^app/, name)

Also nameCleaner option may help you when you need to change the default directory for app code to src, for example:

modules: {
  nameCleaner: path => path.replace(/^src\//, '')


Notifications are on by default.

  • false: deactivate notifications.

  • Array:

    • notifications.levels (Array): By default, only errors trigger notifications. If you want to display success, warning, or informational messages, set this to an array of strings with the levels you want to see, e.g. ['error', 'warn', 'info'].
    • (String): Sets the title used in notifications. Default value is Brunch.
    • notifications.icon (String): Sets the icon of the notification popup.

See documentation for the Loggy package for complete details.


Boolean: determines if minifiers should be enabled or not. Default value is false (true if you run brunch build --production).


TL;DR: To launch a custom Brunch webserver, you'll need to create a file brunch-server.js with a code similar to this:

const express = require('express');
const app = express();

app.use(express.static(__dirname + '/public'));

// AJAX to /action.'/action', (req, res, next) => {
  res.send('POST action completed!');

// Export the module like this for Brunch.
module.exports = (config, callback) => {
  // Server config is passed within the `config` variable.
  app.listen(config.port, function () {
    console.log(`Example app listening on port ${config.port}!`);

  // Return the app; it has the `close()` method, which would be ran when
  // Brunch server is terminated
  return app;

brunch watch --server would automatically load the file.

Object: contains params of webserver that runs on brunch watch --server.

If a brunch-server.js or file exists at the root of your project, Brunch will treat this as your custom web server. This can be overridden with the server.path option.

The server script must export a function that starts your custom server, either as the default exported module. This function should return an instance of http.Server or an object containing a close property assigned to a function that shuts down the server. Examples:

// javascript example using default export and node http core module
module.exports = (port, path, callback) => {
  // your custom server code
  // callback doesn't take any parameters and (if provided) should be called after server is started
  // up to you to respect the `port` argument allowing users to change it from the CLI
  const myServer = http.createServer();
  myServer.listen(port, callback);
  myServer.on('request', (req, res) => { /* do stuff */ });
  return myServer;
// Example using custom `close` method.
module.exports = (port, path, callback) => {
  // custom server code
  return {
    close() { /* code for shutting down server */ }
  • path: (optional) custom path to Node.js file that will be loaded to run your custom server.

If a custom server is not present, Brunch will use pushserve. If using your own, only port from the following options can be set from the config.

  • port: port on which server will run. Default: 3333
  • hostname: hostname on which server will run. Default localhost, which only permits connections from the same computer. Set to to permit access from other computers.
  • base: base URL from which to serve the app. Default: ''
  • indexPath: path to serve when base URL is requested. Default index.html
  • noPushState: respond with 404 instead of indexPath for unknown paths. Default false
  • noCors: disables CORS headers. Default false
  • stripSlashes: removes trailing slashes from URLs. Default false


server: {
  port: 6832,
  base: '/myapp',
  stripSlashes: true
  • command: command to launch a non-Node.js server as a child process. Ex: server: command: 'php -S -t public'


Boolean: enables or disables Source Map generation. Default value is true (enabled), false (disabled) if you run brunch build --production.


  • set to 'old' to use the old @ control character instead of #.
  • set to 'absoluteUrl' to set the sourceMappingURL to the complete URL path starting from config.paths.public
  • set to 'inline' to set the sourceMappingURL to a data URI containing the source map (no .map file will be written)


Integer: Sets an interval in ms which determines how often brunch file list should be checked for new files. Default 65.

On large projects and/or environments with slow disk I/O, the value may need to be increased to ensure a brunch build completes properly in one cycle. However, higher values harm brunch watch performance, so consider changing it in an environment-specific way using overrides.


Object: Alternate config settings to activate via command line switches (--env SETTING). Multiple sets of overrides can be applied at once using a comma-separated list (--env foo,bar).

It is also possible to set an additional environment value using the BRUNCH_ENV or NODE_ENV environment variable. This can be especially useful when combined with dotenv.


brunch watch --env testing
BRUNCH_ENV=testing brunch build
NODE_ENV=production brunch build


overrides: {
  production: {
    optimize: true,
    sourceMaps: false,
    plugins: {autoReload: {enabled: false}}


  • If both files[<type>].joinTo and overrides[<env>].files[<type>].joinTo are defined, the value of files[<type>].joinTo will be overwritten by, not merged with, overrides.
  • If both files[<type>].order and overrides[<env>].files[<type>].order are defined, the value of files[<type>].order will be overwritten by, not merged with, overrides.

In other words, joinTo and order don't merge if defined under overrides, but you still can override one while inheriting the base setting for the other.


Object: Optional settings for chokidar file watching library used in Brunch.

  • usePolling (default: false) Whether to use fs.watchFile (backed by polling), or Polling is slower but can be more reliable.


Object: Optional setting to specify handlers for different moments of building cycle. Possible values:

  • preCompile - Function: Optional callback to be called before brunch starts a compilation cycle. If Promise is returned, it will be awaited.


      hooks: {
        preCompile() {
          console.log("About to compile...");
          return Promise.resolve();
  • onCompile - Function: Optional callback to be called every time brunch completes a compilation cycle. It is passed a generatedFiles array, as well as changedAssets array. Each member of generatedFiles array is an object with:

    • path — path of the compiled file
    • sourceFiles — array of objects representing each source file
    • allSourceFiles array of objects representing each source file — this one also includes files that don't belong to the original type (e.g. if a styles compiler adds a JS module, path would be the concatenated JS file, and one of the allSourceFiles will be a style file

    Each member of changedAssets array is an object with:

    • path — original path of an asset
    • destinationPath — path of an asset in the public directory


      hooks: {
        onCompile(generatedFiles, changedAssets) {
          console.log( => f.path));


You can use CoffeeScript to write configuration files. This way they'll be much shorter and concise. Simply create a file called