Running Your App

A CodeIgniter 4 app can be run in a number of different ways: hosted on a web server, using virtualization, or using CodeIgniter’s command line tool for testing. This section addresses how to use each technique, and explains some of the pros and cons of them.

If you’re new to CodeIgniter, please read the Getting Started section of the User Guide to begin learning how to build dynamic PHP applications. Enjoy!

Initial Configuration & Set Up

  1. Open the app/Config/App.php file with a text editor and set your base URL. If you need more flexibility, the baseURL may be set within the .env file as app.baseURL="". (Always use a trailing slash on your base URL!)

  2. If you intend to use a database, open the app/Config/Database.php file with a text editor and set your database settings. Alternately, these could be set in your .env file.

One additional measure to take in production environments is to disable PHP error reporting and any other development-only functionality. In CodeIgniter, this can be done by setting the ENVIRONMENT constant, which is more fully described on the environments page. By default, the application will run using the “production” environment. To take advantage of the debugging tools provided, you should set the environment to “development”.


If you will be running your site using a web server (e.g., Apache or Nginx), you will need to modify the permissions for the writable folder inside your project, so that it is writable by the user or account used by your web server.

Local Development Server

CodeIgniter 4 comes with a local development server, leveraging PHP’s built-in web server with CodeIgniter routing. You can use the serve script to launch it, with the following command line in the main directory:

> php spark serve

This will launch the server and you can now view your application in your browser at http://localhost:8080.


The built-in development server should only be used on local development machines. It should NEVER be used on a production server.

If you need to run the site on a host other than simply localhost, you’ll first need to add the host to your hosts file. The exact location of the file varies in each of the main operating systems, though all unix-type systems (include OS X) will typically keep the file at /etc/hosts.

The local development server can be customized with three command line options:

  • You can use the --host CLI option to specify a different host to run the application at:

    > php spark serve --host
  • By default, the server runs on port 8080 but you might have more than one site running, or already have another application using that port. You can use the --port CLI option to specify a different one:

    > php spark serve --port 8081
  • You can also specify a specific version of PHP to use, with the --php CLI option, with its value set to the path of the PHP executable you want to use:

    > php spark serve --php /usr/bin/php7.6.5.4

Hosting with Apache

A CodeIgniter4 webapp is normally hosted on a web server. Apache’s httpd is the “standard” platform, and assumed in much of our documentation.

Apache is bundled with many platforms, but can also be downloaded in a bundle with a database engine and PHP from Bitnami.


The “mod_rewrite” module enables URLs without “index.php” in them, and is assumed in our user guide.

Make sure that the rewrite module is enabled (uncommented) in the main configuration file, e.g., apache2/conf/httpd.conf:

LoadModule rewrite_module modules/

Also make sure that the default document root’s <Directory> element enables this too, in the “AllowOverride” setting:

<Directory "/opt/lamp/apache2/htdocs">
    Options Indexes FollowSymLinks
    AllowOverride All
    Require all granted

Virtual Hosting

We recommend using “virtual hosting” to run your apps. You can set up different aliases for each of the apps you work on,

Make sure that the virtual hosting module is enabled (uncommented) in the main configuration file, e.g., apache2/conf/httpd.conf:

LoadModule vhost_alias_module modules/

Add a host alias in your “hosts” file, typically /etc/hosts on unix-type platforms, or c:/Windows/System32/drivers/etc/hosts on Windows. Add a line to the file. This could be “myproject.local” or “myproject.test”, for instance: myproject.local

Add a <VirtualHost> element for your webapp inside the virtual hosting configuration, e.g., apache2/conf/extra/httpd-vhost.conf:

<VirtualHost *:80>
    DocumentRoot "/opt/lamp/apache2/htdocs/myproject/public"
    ServerName myproject.local
    ErrorLog "logs/myproject-error_log"
    CustomLog "logs/myproject-access_log" common

If your project folder is not a subfolder of the Apache document root, then your <VirtualHost> element may need a nested <Directory> element to grant the web server access to the files.


With the above configuration, your webapp would be accessed with the URL http://myproject.local in your browser.

Apache needs to be restarted whenever you change its configuration.

Hosting with Nginx

Nginx is the second most widely used HTTP server for web hosting. Here you can find an example configuration using PHP 7.3 FPM (unix sockets) under Ubuntu Server.

This configuration enables URLs without “index.php” in them and using CodeIgniter’s “404 - File Not Found” for URLs ending with “.php”.

server {
    listen 80;
    listen [::]:80;


    root  /var/www/;
    index index.php index.html index.htm;

    location / {
        try_files $uri $uri/ /index.php$is_args$args;

    location ~ \.php$ {
        include snippets/fastcgi-php.conf;

        # With php-fpm:
        fastcgi_pass unix:/run/php/php7.3-fpm.sock;
        # With php-cgi:
        # fastcgi_pass;

    error_page 404 /index.php;

    # deny access to hidden files such as .htaccess
    location ~ /\. {
        deny all;

Hosting with Vagrant

Virtualization is an effective way to test your webapp in the environment you plan to deploy on, even if you develop on a different one. Even if you are using the same platform for both, virtualization provides an isolated environment for testing.

The codebase comes with a VagrantFile.dist, that can be copied to VagrantFile and tailored for your system, for instance enabling access to specific database or caching engines.

Setting Up

It assumes that you have installed VirtualBox and Vagrant for your platform.

The Vagrant configuration file assumes you have set up a ubuntu/bionic64 Vagrant box on your system:

vagrant box add ubuntu/bionic64


Once set up, you can then launch your webapp inside a VM, with the command:

vagrant up

Your webapp will be accessible at http://localhost:8080, with the code coverage report for your build at http://localhost:8081 and the user guide for it at http://localhost:8082.

Bootstrapping the App

In some scenarios you will want to load the framework without actually running the whole application. This is particularly useful for unit testing your project, but may also be handy for using third-party tools to analyze and modify your code. The framework comes with a separate bootstrap script specifically for this scenario: system/Test/bootstrap.php.

Most of the paths to your project are defined during the bootstrap process. You may use pre-defined constants to override these, but when using the defaults be sure that your paths align with the expected directory structure for your installation method.