What is the PRX file format?
A .prx file is the compiled bytecode output produced when Visual FoxPro processes a .prg source program with its COMPILE command. Rather than native machine code, .prx files contain p-code interpreted at run time by the VFP runtime engine. The compiled format appeared in FoxPro 2.x (DOS and Windows editions) and all Visual FoxPro versions from 3.0 through 9.0 SP2 (2007).
The internal bytecode is proprietary and undocumented; it is not cross-version compatible - a .prx file compiled under VFP 6 will not run correctly under VFP 9. Visual FoxPro also produces compiled files with the .fxp extension; the runtime selects .fxp first when both are present, falling back to .prx if .fxp is absent. Unlike the original .prg source, .prx files are binary and cannot be read as plain text.
The .prx extension is occasionally confused with the Sony PSP PRX format - PlayStation Portable relocatable executables used for firmware plugins - which is an entirely unrelated binary format. Microsoft ended Visual FoxPro development in 2007; extended support concluded January 13, 2015. Running VFP applications today typically requires Windows XP/Vista compatibility modes or a virtual machine. The VFPX open-source community maintains extensions to the frozen VFP codebase, including tooling for DBF database access.
Security & safety
RISK: MEDIUM.prx files are interpreted bytecode executed by the VFP runtime - they can perform file system and registry operations within the limits of what FoxPro allowed. In modern context: a .prx file from an untrusted source should not be executed. The main concern today is legacy system vulnerabilities; VFP 9.0 has received no security patches since 2015.
Format details
in a nutshell- PlayStation Portable PRX (PSP Plugin/Firmware) - PRX on PSP is a Relocatable Executable (ELF-based, MIPS) used for PSP firmware modules and plugins - completely unrelated to FoxPro.
- Polaris Office Template - Some versions of Polaris Office use .prx as a template or extension file; niche, mobile-office context.
Programs that open PRX files
Windows1 app
Microsoft Visual FoxPro 9.0
Paid Run the compiled .prx from within the VFP environment: 'DO program.prx' in the Command Window, or the runtime (VFP9R.DLL) executes it as part of an application. Technical details
deep spec| File encoding | Binary (compiled p-code bytecode; not human-readable) |
| Byte order | Little-endian (x86 Windows target platform) |
| Bytecode type | Interpreted p-code executed by the VFP runtime, not native machine code |
| Source relationship | Compiled from a `.prg` source file using the VFP `COMPILE` command; source and compiled file share the same base name |
| Version binding | Bytecode is not cross-version compatible - `.prx` compiled under VFP 6, 7, 8, or 9 runs only on that version's runtime |
| Runtime file preference | VFP runtime executes `.fxp` if present in the same directory; falls back to `.prx` if `.fxp` is absent |
| Typical file size | 1 KB - 500 KB depending on program complexity |
| Format documentation | Proprietary and undocumented by Microsoft; no public specification exists for the bytecode structure |
| Operating system | Windows 95 through Windows XP/Vista (primary VFP 9 targets); possible under Wine on Linux |
| Product status | Visual FoxPro 9.0 SP2 is the final version; extended support from Microsoft ended January 13, 2015 |
| Extension conflict | Unrelated to Sony PSP `.prx` (PlayStation Relocatable Executable), a firmware plugin format for the PSP handheld |
| Related formats | `.prg` (FoxPro source program), `.fxp` (alternate compiled format), `.dbf` (FoxPro database table) |
| Released | circa 1987 (FoxBase/FoxPro era); .prx extension used through Visual FoxPro 9.0 (2004) |
| Latest version | Visual FoxPro 9.0 SP2 (2007) - final version; product EOL |
PRX conversions
Community Q&A
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