vNext (ASP.NET 5) is Microsoft's new platform that is opensource and cross platform. which means you can change code according to your needs, distribute it and run on any platform as you like (Windows, MacOs or Linux). Microsoft has been working on this stuff for quite a long time and now it is very near of first release in this quarter of the year (Q1 2016). Currently vNext/ASP.NET 5 is in Release Candidate Update 1.