In conjunction with the release of SQL Server 2016, Microsoft has announced that the Developer Edition of SQL Server will be free. In order to take advantage of this offer, you will need to be a member of Microsoft’s Visual Studio Dev Essentials program.
The Visual Studio Dev Essentials program, which is also free, is the channel through which Visual Studio Community and Visual Studio Code are offered. Also included are various Azure products, Microsoft R Server, and free training from a variety of vendors.
SQL Server 2016 Developer edition differs from their other free offering, SQL Server Express, in two ways. Unlike SQL Server Express, it cannot be used in production environments. However, it does have the advantage of including all of the SQL Server Enterprise features. This allows developers to experiment with Clustered Columnstore, Memory Optimized Tables, and other advanced features.
There is a downside to this however- there is no developer equivalent to the less expensive SQL Server 2016 Standard edition. So developers planning on targeting that edition need to be extra careful that they don’t accidentally introduce an Enterprise-only feature into their codebase.