One major change that differentiate Magento 2 from Magento 1 is the introduction of development Modes.
What are Magento modes?
In Magento there are three modes of operation for deployment in a development or production environment:
Production modes. The fastest one is production and recommed to run a live magento website in this mode .
Developer modes are used for debugging purposes and not recommended to use for a live site.
And one more mode for maintenance: Intended to prevent access to a site while it is being updated or reconfigured, this mode
Enables you to deploy the Magento application on a single server without changing any settings. However, default mode is not optimized for production.
To deploy the Magento application on more than one server or to optimize it for production, change to one of the other modes.
Intended for development only, this mode:
Intended for deployment on a production system, this mode:
Intended to prevent access to a site while it is being updated or reconfigured, this mode:
NOTE: Adobe Commerce on cloud infrastructure supports only the production and maintenance modes.