PRJ File

What are PRJ files and how to open them

Are you having problems opening a PRJ file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your PRJ files.

What is a PRJ file?

PRJ files have multiple uses, and Project is one of them. Read more about the other uses further down the page.

Project File

Files that contain the .prj file extension are most commonly used to store project files. The .prj file extension is a generic extension that is used by a variety of different project applications. PRJ files typically contain the project settings and other project data, including references to other files that the related project may use.

Some applications that use the .prj file extension for project files include Maestro, Microsoft Visual Basic, Visual Cafe, Turbo C, FireFly SDK, and AwpHelp.

Although many software applications use the .prj file extension, not all PRJ files are interchangeable across all applications. This means that a PRJ file that has been created in one application may not be able to be opened with another application that uses the .prj file extension due to differences in the format of the file type.

How to open PRJ files

Important: Different programs may use files with the PRJ file extension for different purposes, so unless you are sure which format your PRJ file is, you may need to try a few different programs.

While we have not verified the apps ourselves yet, our users have suggested ten different PRJ openers which you will find listed below.

Last updated: August 10, 2026

All known file formats using extension .PRJ

While Project File is a popular type of PRJ-file, we know of 22 different uses of the .PRJ file extension. Different software may use files with the same extension for different types of data.

UltraEdit Project

UltraEdit Project files store configuration and metadata for a collection of files that are grouped together under UltraEdit or UEStudio as a "project." These .PRJ files define which files and folders belong to the project, how they are organized, which optional tools or settings to use, and how to recall the user's workspace when the project is reopened. Their primary function is to allow the user to save and load sets of related files, directory groupings, filters, and view state so that work on a multi-file task can be resumed without having to manually reopen or reconfigure every component.

UltraEdit writes the .PRJ file when you create a new project or workspace by choosing New Project in the Project menu. You then use the Project Settings dialog to add files, folders (real or virtual "groups"), set filters (for showing only certain file types), optionally assign syntax‐highlighting wordfiles or templates specific to this project, and determine whether file paths are stored absolutely or relatively to the project directory. When you later open the .PRJ file, UltraEdit reloads the file/folder list, workspace (which files were open, caret/window positions), and all project‐specific settings.

Internally the .PRJ is human‐readable (INI‐style) and begins with "[ProjectID]" at byte offset 0. It contains keywords such as PROJECT INFORMATION, PROJECT WORDFILE, PROJECT TAGFILE or CTAGS, FILTER and GROUP or FILES sections, with settings like "USE RELATIVE DIRECTORY" or "RELATIVE TO PROJECT FILE" appearing.

PRJ opener for Windows

We have identified one PRJ opener that is compatible with this specific type of PRJ file.

3D Studio Project

We know that one PRJ format is 3D Studio Project. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

Anjuta Project

We know that one PRJ format is Anjuta Project. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

ASIC Project

We know that one PRJ format is ASIC Project. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

Autem PLC/SPS Analyzer Pro Project

We know that one PRJ format is Autem PLC/SPS Analyzer Pro Project. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

Borland C/C++ Project

We know that one PRJ format is Borland C/C++ Project. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

Clarion Project

We know that one PRJ format is Clarion Project. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

Ergo!pro Project

We know that one PRJ format is Ergo!pro Project. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

FireFly SDK Designer Project

We know that one PRJ format is FireFly SDK Designer Project. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

Harvard Total Project Manager Project

We know that one PRJ format is Harvard Total Project Manager Project. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

MADE Engine Project/game

We know that one PRJ format is MADE Engine Project/game. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

MADE Project

We know that one PRJ format is MADE Project. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

MATLAB Project

A MATLAB Project file with the extension .PRJ is used by The MathWorks MATLAB software to represent either a project or a toolbox/app-packaging project. These files let you save and restore configurations or definitions so that you can close MATLAB or move tasks between sessions, and later resume development without loss of settings or composition. MATLAB writes .PRJ files when you set up a project using the MATLAB "Projects" feature, when packaging apps as installable .MLAPPINSTALL files (in older releases), or when making toolbox tasks that include deployment or packaging settings. MATLAB reads .PRJ files to reopen projects, to load settings and labels, to configure environment paths and dependencies, or to package a toolbox or app.

A .PRJ project file stores various project metadata in a structured, XML format. Its contents typically include which source files are part of the project, dependencies, toolbox or app name, version, description, author, excluded files, platform compatibility, and any startup or shutdown shortcuts or labels. MATLAB provides commands to work with .PRJ files programmatically: for example, matlab.apputil.create(prjfile) is used to create or modify an app project file for packaging into an installable .MLAPPINSTALL file, and matlab.addons.toolbox.packageToolbox(projectFile) packages a toolbox project (.prj) into a toolbox install file (.mltbx).

The .PRJ files by MATLAB are plain-text and structured as XML documents. You can edit them manually - or more safely use MATLAB functions like readstruct or writestruct with FileType='xml' - to inspect or change specific configuration fields such as version, included/excluded file lists, or other metadata.

Programs that open these PRJ files

We have identified one PRJ opener that is compatible with this specific type of PRJ file.

My House Project

We know that one PRJ format is My House Project. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

Pacific C Compiler Project

We know that one PRJ format is Pacific C Compiler Project. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

PADAUK Developer Studio Project

We know that one PRJ format is PADAUK Developer Studio Project. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

Shapefile Projection Metadata

We know that one PRJ format is Shapefile Projection Metadata. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

Tornado 3D Project

We know that one PRJ format is Tornado 3D Project. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

Total Project Manager Project

We know that one PRJ format is Total Project Manager Project. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

Virtual T IDE Project

We know that one PRJ format is Virtual T IDE Project. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

Xenosaga Sound Info

We know that one PRJ format is Xenosaga Sound Info. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

Various apps that use files with this extension

These apps are known to open certain types of PRJ files. Remember, different programs may use PRJ files for different purposes, so you may need to try out a few of them to be able to open your specific file.

Help us help others

File.org helps thousands of users every day, and we would love to hear from you if you have additional information about PRJ file formats, example files, or compatible programs. Please use the links below or email us at submit@file.org to discuss further.