Interview process may have from 2 to many stages and basically depends on customer. Initially HR person would contact you for a basics screening like CV, mindset etc. and tell you some details about project. After that you may be invited for a technical interview with a technical person from the company. In my case that interview was relatively simple and didn't go beyond typical questions about C#, .NET and object oriented programming. If that interview is successful you usually would have at least one more with a customer. In my case it was basic non-technical think, however it depends on client.