Because of the read-only filesystem, you cannot change modes in the remote cloud environments. Do not attempt to change modes by modifying the app/etc/env.php file because the ece-tools package overwrites the file based on multiple configuration sources.

Adobe Commerce on cloud infrastructure automatically runs the application in maintenance mode during a deployment, which takes your site offline until the deployment is complete. Otherwise, the application remains in production mode. See Deployment process in the Commerce on Cloud Infrastructure guide.

If you use Cloud Docker for Commerce as a development tool, you can deploy your cloud infrastructure project in a Docker environment in developer mode, but performance is slower because of additional file synchronization operations. See Deploy the Docker environment in the Cloud Docker for Commerce guide.

Default mode

The default mode enables you to deploy the Commerce application on a single server without changing any settings. However, default mode is not optimized for production because of the adverse performance impact of static files. Creating static files and caching them has a greater performance impact than generating them using the static files creation tool.

In default mode:

Exceptions are written to log files instead of display
Static view files are cached
Hides custom X-Magento-* HTTP request and response headers

Commerce operates in default mode if no other mode is specified.

Developer mode

The developer mode is recommended for extending and customizing the Commerce application. Static view files are not cached, but written to the pub/static directory on demand.

In developer mode:

Enables automatic code compilation and enhanced debugging
Uncaught exceptions display in the browser
System logging in var/report is verbose
An exception is thrown in the error handler, rather than being logged
An exception is thrown when an event subscriber cannot be invoked
Shows custom X-Magento-* HTTP request and response headers

Production mode

The production mode is best for deploying the Commerce application on a production system. After optimizing the server environment, such as the database and web server, you should run the static view files deployment tool to write static view files to the pub/static directory. This improves performance by providing all necessary static files at deployment instead of forcing the Commerce application to dynamically locate and copy (materialize) static files on demand during run time.

Some fields, such as the Advanced and Developer system configuration sections in the Admin, are not available in production mode. For example, you cannot enable or disable cache types using the Admin. You can enable and disable cache types only using the command line.

In production mode:

Static view files are served from the cache only
Errors and exceptions are logged to the file system and are never displayed to the user
Some configuration fields in the Admin are not available

Maintenance mode

The maintenance mode limits or prevents access to a site during improvements, updates, and configuration tasks. By default, the site redirects visitors to a default Service Temporarily Unavailable page.

You can create a custom maintenance page, manually enable and disable maintenance mode, and configure maintenance mode to allow visitors from authorized IP addresses to view the store normally. See enable and disable maintenance mode in the Installation Guide.

If you are using Commerce on cloud infrastructure, the Commerce application runs in maintenance mode during the deploy phase. When the deployment completes successfully, the Commerce application returns to running in production mode. See Deployment hooks in the Commerce on Cloud Infrastructure guide.

In maintenance mode:

Site visitors are redirected to a default Service Temporarily Unavailable page
The var/ directory contains the .maintenance.flag file
You can limit visitor access based on IP addresses

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