CAPX File

What are CAPX files and how to open them

Are you having problems opening a CAPX 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 CAPX files.

What is a CAPX file?

CAPX files have multiple uses, and Capella CapXML Music Notation is one of them. Read more about the other uses further down the page.

Capella CapXML Music Notation

These CAPX files contain score sheets created in Capella's notation software, software for creating musical score sheets. Currently, Capella is only available on Windows. In these CAPX files, the nodes in use are single chords with one or more notes.

How to open CAPX files

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

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

Last updated: August 25, 2026

All known file formats using extension .CAPX

While Capella CapXML Music Notation is a popular type of CAPX-file, we know of 2 different uses of the .CAPX file extension. Different software may use files with the same extension for different types of data.

Construct Compressed Game Project

Construct Compressed Game Project files store entire game projects created with Construct 2 in a single archive. They include layouts, event sheets, animations, images, sounds, physics data, project settings and all assets needed for the game's logic and presentation. This format makes it simple to save, share, upload or back up a complete project as one file.

These files are produced by the Construct 2 game development tool when saving a project as a single file. Under the "Save As Single File" mode Construct 2 compresses all project folders and files into one .capx archive. When opened back in Construct 2, the archive is unpacked again internally so the project can be edited, previewed or exported. Alternately, Construct 2 supports "folder projects" in which each component is stored as a separate file rather than inside one archive.

Internally a .capx file is exactly a ZIP-format archive. It begins with the usual ZIP file signature (bytes 0x50 0x4B 0x03 0x04). Inside are project-structure folders like Layouts, Animations and Event Sheets; XML-formatted files defining events, UI state, resources; bitmap image files (PNG) including IHDR, IDAT, IEND chunks; and resource identifiers such as .caproj and .uistate.xml.

Various apps that use files with this extension

These apps are known to open certain types of CAPX files. Remember, different programs may use CAPX 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 CAPX file formats, example files, or compatible programs. Please use the links below or email us at submit@file.org to discuss further.