Developer environments are not new - it's always been possible to provision a single developer environment for each user by subscribing to the development plan.
The benefit of the developer environment is that it offers a segregated area for app makers to experiment and to play, particularly for users without a Dataverse licence.
An exciting new feature that's been released in preview this week is the ability to provision up to 3 developer environments per user.
For further reading, there are more details in the announcement in official Microsoft blog post here
What are the features and limitations of the new developer environments?
The primary benefits of a developer environment are that it provides full Dataverse capabilities, it enables users to use premium connectors, and allows users to create and share those apps with other users in their organisation.
An added benefit is that the Dataverse database in the environment isn't factored into the overall tenant capacity. Therefore, administrators don't need to worry about developer environments using up excessive storage space and incurring additional cost.
There is however a 2GB storage limitation on each developer environment. Also, unused developer environments are automatically deleted after 90 days of inactivity.
How to create a new or additional developer environment
At the time of writing, this feature is in preview so the first step is to navigate to the 'preview' Maker Portal through the following URL.
From the Maker Portal, click the Environment name in the banner. From here, you can click the 'Try it now' button within the 'Need your own environment (it's free)' section.
This opens a panel where we can enter an Environment name and select a region.
Clicking the 'accept' button creates the new environment.
How to create new developer environments from the Admin CentreIt's also possible to create a new developer environment from the Power Platform Admin Center (PPAC).
To do this, navigate to the Power Platform Admin Center.
Click 'Environments' from the left-hand pane and click the 'New' button from the toolbar. This opens the 'New environment' panel in the right-hand part of the window. From this panel, we choose the 'Developer' option in the 'Type' dropdown to create a developer environment.
How to reset a developer environment
It's possible to revert a developer environment and reset it to its default state. This will delete everything in the environment including all data, apps, and flows.
To do this, click the '3 dots' against the environment in the Power Platform Admin Center. This opens a context menu that includes many features, including the option to copy, backup, restore, and delete the environment. One of the options here is 'Reset'.
Clicking 'Reset' menu item opens the panel that's shown beneath. Clicking the 'Reset' button will reset the environment.
How to copy a developer environment to a sandbox environment
When we've developed something in the developer environment and want to begin the process to make it live, we can start this process through the 'Copy environment' option. This enables us to copy the data and table schemas to a sandbox environment.
It's now possible to create up to 3 developer environments per user and this post summarised this new preview feature