What is the PRO file format?
.pro is a generic file extension used by many different applications. .pro files can be roughly divided into two types - those which store profile information and those which contain project configuration data. A profile file can be considered a type of configuration file, as it stores data related to user or system settings; a project file, however, contains settings or configuration specific to a particular application environment.
The most widely known use is the Qt qmake project file - a plain-text build script that defines SOURCES, HEADERS, TARGET, and TEMPLATE via key = value assignments, which qmake converts to platform-native Makefiles. Other programs using the .pro extension include PTC Creo (assembly data), KiCad (PCB projects before version 6), and IBM Cognos TM1. From Qt 6 onward, .qbs and CMake are the preferred build systems.
Given a random .pro file, it is hard to determine which application it belongs to. Most .pro files are saved in plain text format, so it is possible to open such a file and look for recognizable keywords - such as QT +=, SOURCES +=, or TEMPLATE - as hints about its origin and purpose. Opening unknown files is potentially risky from a security standpoint, so caution is advised.
Security & safety
RISK: LOWMost .pro files are plain text (project configs, source, settings) and contain no executable code, so reading one is safe. The real risk is misidentification, not malware: because the extension is generic, double-clicking may launch the wrong program or none at all - open it in a text editor first to see what it is. As always, be cautious of any file whose real nature is unclear or that arrived unexpectedly, and don't run build scripts from untrusted projects without reviewing them.
Format details
in a nutshell- PTC Pro/ENGINEER (now Creo) part/data file - Older Pro/ENGINEER could use .pro for config/part-related files; opened in PTC Creo. This is the program the source database flagged as 'recommended' for .pro.
- KiCad project file (pre-v6) / Prolog source - KiCad stored projects as .pro before v6 (now .kicad_pro JSON); Prolog source code also uses .pro/.pl, opened by a Prolog interpreter.
- TurboFloorPlan / IBM Cognos TM1 process - TurboFloorPlan saves projects as .pro; Cognos TM1 uses .pro for TurboIntegrator process scripts - each opens only in its own app.
Programs that open PRO files
Windows4 apps
Qt Creator
Open-source For a Qt project: File > Open File or Project and select the .pro; Qt Creator loads and builds it. Free open-source edition available. 
A text editor (Notepad++ / VS Code)
Open-source Open any .pro as text to read it and identify which program made it before choosing the right app.
PTC Creo (Pro/ENGINEER)
Paid If the .pro is a Pro/ENGINEER/Creo file, open it in PTC Creo. (db 'recommended' app; CAD, paid.)
KiCad
Open-source If it's an older KiCad project .pro, open it in KiCad; v6+ converts/uses it (newer projects are .kicad_pro). 
macOS2 apps
A text editor (TextEdit / VS Code)
Freemium Open the .pro as text to inspect it and work out which program owns it. 
Linux2 apps
Qt Creator
Open-source Open the Qt .pro in Qt Creator; or run 'qmake' on it from a terminal to generate a Makefile.
A text editor
Open-source Open the .pro to read it; for Prolog .pro, load it in a Prolog interpreter (e.g. SWI-Prolog). Technical details
deep spec| File encoding | Plain UTF-8 or ASCII text; no binary header or magic bytes |
| MIME type | text/plain |
| Primary syntax | key = value and key += value variable assignments; lines beginning with # are comments |
| Core variables | SOURCES, HEADERS, FORMS, TARGET, TEMPLATE, CONFIG, QT |
| TEMPLATE values | app (executable), lib (shared or static library), subdirs (recursive sub-projects) |
| Build tool | qmake - reads the .pro file and outputs Makefiles or IDE project files |
| Platform scope blocks | Conditional blocks such as win32 { }, macx { }, unix { } apply platform-specific settings |
| Variable expansion | $$VAR syntax references other qmake variables (e.g., $$TARGET, $$PWD) |
| Include mechanism | .pri files (Qt project include snippets) pulled in with include(path.pri) |
| Qt module dependencies | QT += widgets network sql adds Qt modules to the build |
| Successor formats | Qt Build System (.qbs) and CMake (CMakeLists.txt) recommended from Qt 6 onward |
| Other format uses | Also used by PTC Creo (assembly data), KiCad v5 and earlier (PCB project), IBM Cognos TM1, Prolog environments |
| Generated output | Windows: Makefile (MinGW) or .vcxproj (MSVC); macOS: Makefile or .xcodeproj; Linux: Makefile |
| Cross-platform support | A single .pro file can target Windows, macOS, and Linux from the same source tree |
| Released | Qt / qmake, early 2000s |
| Open standard | Yes · royalty-free |
| Specification | doc.qt.io |
PRO conversions
Community Q&A
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