A PRJ file contains a project that may be created by a variety of different programs, such as Microsoft Visual Basic and Autodesk AutoCAD. It typically saves project data and settings and may include references to other files used by the project.

The .prj file extension is a generic project file extension, which means that it may be used by multiple programs to save project information. However, just because a program saves a project as a PRJ file does not mean that it can open PRJ files created by other programs. There are a large number of programs that save projects with .prj extensions. If you encounter a PRJ file and you do not know which program created it, it may be difficult to find a program that can open it. If you need to open a PRJ file in Windows you can right-click the file and select Properties or Open with to view possible programs that can open the file type. You can also choose Search the Microsoft Store in the Open with option in Windows 10 to look for other software options to open the unknown PRJ file type. If you need to open a PRJ file in macOS, you can right-click the file and select Get Info to view possible programs that can open the file type. Also, the following list of programs is a reference of possible file associations for PRJ files.