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Extending / Bundled Extensions / Quick Start

Note: You are currently reading the documentation for Bolt 3.7. Looking for the documentation for Bolt 5.2 instead?

This guide will step through an example of the required steps to create your first Bundle. It should be noted that there is quite a bit of flexibility and customisation that can be done with a Bundle, but for the sake of simplicity the example will adhere to the following:

  • The Bundles' PHP loader class will be called CustomisationExtension in a file named src/Site/CustomisationExtension.php
  • The PHP code for this Bundle will use the namespace of Bundle\Site

For more information see the Building Bundles page.

Bundle Extension Class

Bolt extensions & Bundles all require a PHP class that acts as a load for your extension's configuration logic.

In its simplest form, our loader class src/Site/CustomisationExtension.php would look like this.


namespace Bundle\Site;

use Bolt\Extension\SimpleExtension;

 * Site bundle extension loader.
class CustomisationExtension extends SimpleExtension

Note: the class name must match the file name.

Composer Autoloader

In order for PHP to be able to find your Bundle, it requires a psr-4 entry in the autoload section your site's composer.json file.

The end result would look similar to this:

    "require": {
        "php": "^5.5.9 || ^7.0",
        "bolt/bolt": "^3.7",
        "passwordlib/passwordlib": "^1.0@beta"
    "minimum-stability": "beta",
    "prefer-stable": true,
    "scripts": {
        "post-install-cmd": [
        "post-update-cmd": [
        "post-create-project-cmd": [
            "nut extensions:setup"
    "autoload": {
        "psr-4": {
            "Bundle\\": "src/"

The important things to note are:

  • PHP namespace of your classes, in this example we are using Bundle\Site
  • Backslashes \ in namespaces must be doubled, i.e. \\
  • Namespaces must end with two backslashes, i.e. \\
  • The directory path specified must contain the loader class file, in this example the file is located in src/Site

Composer can then be run with the dump-autoload command, e.g.

composer dump-autoload

Using default options, running the dump-autoload command will create the file vendor/composer/autoload_psr4.php that you can interrogate should you need to see the end result.

Activating the Bundle

Finally, you need to add an entry to your .bolt.yml in the root of your site. By default this file does not exist, so you may need to create it yourself.

For each Bundle, simply add a line under the extensions key, with the fully qualified class name of the loader class.

    - Bundle\Site\CustomisationExtension

Configuring the Bundle

Configuration settings for your bundle will be read from a YAML file in the app/config/extensions/ directory called customisation.bundle.yml.

Adding Functionality

At this stage your Bundled Extension should now be able to be seen in the "Bundled Extensions" section of your Extensions page. Now it is time to add the functionality you desire.

For details on how to build extension logic into your new Bundle, see the "Extending Bolt" Intermediate & Advanced sections.

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