Mostly pick one with a big community that other are using for quick prototypes. And (as others have said) ignore scaling unless scale is what you are prototypin

Mostly pick one with a big community that other are using for quick prototypes. And (as others have said) ignore scaling unless scale is what you are prototyping. Use SQL to start. (MySQL/PostGres/Etc..) It's better to denormalize if you need scale then have to normalize noSQL data if needed at the app layer (maybe that's up for debate?). C#/.net It's the one I know the best and supported for both fast prototyping (.net MVC apps) and scale [Linux and Windows]. Desktop Apps / Mobile / AWS Lambda etc... I use MSSQL for my data, but have used MySQL in the past.