XMP (Extensible Metadata Platform) files are small text files that store editing information for your images. Think of them as a recipe card that tells photo-editing software exactly how to display an image — exposure adjustments, colour corrections, cropping, sharpening, and hundreds of other potential edits.
They're known as ‘sidecar files’ because they sit alongside your RAW image files, holding all the editing instructions without modifying the original image itself. This non-destructive approach is one of the cornerstones of professional photography workflows.
XMP files are plain text and can even be opened in a text editor (though we don't recommend editing them by hand). They use XML formatting to store metadata and editing parameters in a way photo-editing software can read and interpret.