Annotation Data Formats in UWP: XFDF vs. JSON

In addition to reading and writing annotations embedded into a PDF, PSPDFKit also allows you to use external files to manage annotations.

Separating annotations and form data from the underlying document

PSPDFKit supports reading and writing annotations in the following external data file formats:

  • XFDF (XML Forms Data Format)

XFDF (XML Forms Data Format)

PSPDFKit has full support for reading and writing XFDF.

XFDF is an XML-based standard from Adobe XFDF (ISO 19444-1:2016) for encoding annotations and form field values. It’s compatible with Adobe Acrobat and many other third-party PDF applications.

XFDF is a representation of all annotation and form data inside a PDF document at a point in time. It doesn’t have a concept of differentials (diffs) for managing changes made by multiple users annotating the same PDF simultaneously, and it cannot store deleted annotations. This makes XFDF a challenging format to use for comparing changes, managing conflicts, and synchronizing annotations across users, devices, or sessions.