The new April 2019 release for Dynamics 365 Business Central introduced lots of new features and one of the most interesting is for sure the possibility to have more than one online sandbox.
With this new release (platform 14) you will be able to create up to three sandbox environments at a time per tenant (with different names) and:
Related to extensions development and management, now:
I often see many people that develop extensions directly by using the online sandbox from Visual Studio Code. This is a way of work that personally I don’t love too much and that I never recommend (I prefer to develop locally and then use the online sandbox for final testing and for customer’s testing), but if you’re doing that remember that actually, also if you have multiple sandboxes, you cannot connect from Visual Studio Code to the sandbox environment you want, but only to the main one (which is /sandbox as url).
In the future, you will be able to specify the sandbox name to connect from Visual Studio Code by using a new sandboxName parameter in your launch.json configuration file:
A final last consideration: please don’t abuse on sandboxes, use them when you really need them and avoid to recreate N sandboxes every day.