Interop is a way in which one programming language can talk with another. In .Net, we almost exclusively talk about .Net applications talking to C++ applications. Excel interop is a technology defined by Microsoft. It allows people to use excel from C# by counselling an installed instance of excel. This seems like a great idea until we realize the excel must be installed on the target machine that might include your web server or the Docker instance or Azure many places where Excel can never be installed and Microsoft does not actually allow licensing. We highly recommend against using excel interop in any web application or any application where you may be distributing to a target system that may not have the exact correct version of Excel installed.

Do I need to install Excel on my server to use Excel in a C# application? No, you do not. If you use IronXL to work protect cell in your C# application, you do not need Excel to be installed on any computer yet you can achieve all the functions that Excel provides.

Can IronXL work without interop? IronXL does not require interop to create, edit, import generate and export Excel documents. That is why it's become such a popular C3 excel library.

Is there a use case where you would use interop in your project with IronXL? We cannot think of any reason to use Excel interop with IronXL. However, IronXL allows you to use data from any source to create an Excel forward file. So if you have interrupt with another C++ application, for example, a proprietary system, IronXL can take that data and write it to excel, but we will not require an Excel interop and we will not require Excel to be installed on your host machine. This is important for .Net core, where Excel cannot be installed in an interop compatible format for Mac and Linux targets or hosts on the internet.

What features can you use without interop in IronXL? IronXL can achieve almost anything that can be achieved within the Excel application.