How to open FSI files

Did your computer fail to open a FSI file? We explain what FSI files are and recommend software that we know can open or convert your FSI files.

What is a FSI file?

The FSI file extension indicates to your device which app can open the file. However, different programs may use the FSI file type for different types of data.

While we do not yet describe the FSI file format and its common uses, we do know which programs are known to open these files, as we receive dozens of suggestions from users like yourself every day about specific file types and which programs they use to open them.

We are continually working on adding more file type descriptions to the site, so if you have information about FSI files that you think will help others, please use the Update Info link below to submit it to us - we'd love to hear from you!

Generic FSI

These apps are known to open certain types of FSI files. Since many different programs may use FSI files for different purposes, you may need to try a few of the apps to open your specific FSI file.

Microsoft Visual Studio CodeMicrosoft Visual Studio CodeUser submitted
FlightScope Firmware WriterFlightScope Firmware WriterUser submitted
Microsoft Visual Studio CTPMicrosoft Visual Studio CTPUser submitted

Try a universal file viewer

Try a universal file viewer like Free File Viewer. It can open over 200 different types of files - and most likely yours too. Download Free File Viewer here.

We have not verified any programs that we know for certain can work with FSI-files on Mac. If you know one, please use the Suggest link below and tell us about it!
We have not verified any online services that we know for certain can work with FSI-files. If you know one, please use the Suggest link below and tell us about it!