Data file

What is a .qxp file?

A .qxp file is a QuarkXPress Data File. This is a data file — structured information used by a program rather than read directly. Confusingly, this extension has been used by 19 different formats over the years — they're all listed below.

This extension has been used by more than one format

19 different formats have claimed .qxp over the years, so two files with the same extension aren't necessarily the same kind of thing.

How to open a .qxp file

Start with the program that produced it; that's almost always the right tool.
Open it in a text editor to see whether it's readable text or binary.
For database formats, DB Browser for SQLite or LibreOffice Base can often import it.

The registry records this extension against QuarkXPress Data File, QuarkXPress Project, QuarkXPress Project and others, so software from that family is the most likely match.

How to convert a .qxp file

If you can view the data, exporting to .csv is usually the most portable option.

MIME type

When a .qxp file travels over the web, servers label it with this MIME type:

application/vnd.Quark.QuarkXPress

What's a MIME type?

The technical record

For archivists, developers and the merely curious: these are the PRONOM registry entries for .qxp.