DFD File

What are DFD files and how to open them

Are you having problems opening a DFD 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 DFD files.

What is a DFD file?

A .DFD file is an ATK Data Flow Diagram file.

ATK Data Flow Diagram files are part of a suite of tools called ATK designed for creating, analyzing, and maintaining data flow diagrams and their associated data dictionaries. The toolset includes GED, a graphic editor that lets diagrams be entered and manipulated using standard DFD symbols and conventions; it writes out diagram files in a plain-text ASCII format which other tools in the suite (such as the dictionary builder, evaluators, report generator, and PostScript exporter) use.

Diagram files store both the structure of the flow - processes, data stores, external entities, and the flows connecting them - and labels or decomposition of processes (up to eight levels below a context diagram). The ATK tools enforce consistency between the data flow diagram files and the data dictionary: evaluators check for conformance to structured analysis methodology.

Files begin with the ASCII header string "DfdTitle" which identifies them as ATK DFD files.

How to open DFD files

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

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

Last updated: October 27, 2026

Various apps that use files with this extension

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

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