CSA File

What are CSA files and how to open them

Are you having problems opening a CSA 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 CSA files.

What is a CSA file?

CSA files have multiple uses, and CADSTAR Schematic Archive is one of them. Read more about the other uses further down the page.

CADSTAR Schematic Archive

CADSTAR Schematic Archive files hold design data for electronic circuit schematics produced with the CADSTAR software from Zuken. They store the complete structure of a schematic - including symbol definitions, parts, nets, display attributes, and sheets - exported in a human-readable text/archive form. The archive format allows the design to be moved, converted, inspected, or imported by other tools without needing CADSTAR's original binary schematic file.

These files are produced when a schematic design in CADSTAR is saved or exported into its archive (ASCII) form, taking the binary schematic format and converting it into structured text. Once created, they are used by migration workflows - such as importing into Altium Designer or KiCad - where tools read the text version to recreate symbols, nets, and drawings in the target design environment. They are also used when exporting schematic symbol libraries or template designs as part of library or design migration.

Internally the format is a tokenized, parenthesized structure similar to Lisp s-expressions. The top-level element is CADSTARSCM, under which are nodes like HEADER, ASSIGNMENTS, LIBRARY, DEFAULTS, PARTS, SHEETS, SCHEMATIC, and DISPLAY. The HEADER node includes fields such as FORMAT, JOBFILE, GENERATOR, RESOLUTION, and TIMESTAMP defining version, original file name, tool version, units (e.g. "METRIC HUNDREDTH MICRON"), and export time. Symbol definitions appear in LIBRARY, symbol use and net connections in SCHEMATIC, etc. Version number in the FORMAT node determines how coordinate and angular units are encoded. Byte-signature detection includes the ASCII sequence starting with (.CADSTARSCM.(HEADER.(FORMATDESIGN at file start.

How to open CSA files

Important: Different programs may use files with the CSA file extension for different purposes, so unless you are sure which format your CSA 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 CSA openers which you will find listed below.

Last updated: September 19, 2026

All known file formats using extension .CSA

While CADSTAR Schematic Archive is a popular type of CSA-file, we know of 3 different uses of the .CSA file extension. Different software may use files with the same extension for different types of data.

Compute Shaders Archive

We know that one CSA format is Compute Shaders Archive. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

CSArc Compressed Archive

We know that one CSA format is CSArc Compressed Archive. 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 CSA files. Remember, different programs may use CSA 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 CSA file formats, example files, or compatible programs. Please use the links below or email us at submit@file.org to discuss further.