What is a .xml file?

About the format

An .xml file is structured text: data wrapped in nested, named tags, readable by humans and parsers alike. On Windows you'll meet XML as configuration (.NET app.config files, scheduled-task definitions exported from Task Scheduler, Sysprep answer files), as data interchange, and inside things that don't look like XML at all — modern Office documents (.docx/.xlsx) are ZIP archives full of XML parts, and Windows Event Log entries render to XML in Event Viewer's Details tab. Opening one safely is trivial: any text editor, or a browser for collapsible pretty-printing. Editing one is where care matters — XML is strict (every tag closed, correct nesting, special characters escaped), and one malformed bracket makes the whole file unreadable to its consumer, so copy before editing. XML files themselves don't execute, though a config file controls how its program behaves, which is exactly why installers and admin tools lean on them.

How to open a .xml file

Is a .xml file dangerous?

The file is data. (For developers: parsing untrusted XML has classic pitfalls like entity expansion — a builder's concern, not an opener's.)

Related file types