FDF

FDF (Acrobat Forms Data Format) is a format for storing and transferring data entered into a form in a PDF file. It is a mostly-text format based on PDF.

FDF may be embedded in a PDF file; or it may be stored on its own in an .fdf file; or it may only exist "on the wire", and not be stored in a file at all.

If you try to open an .fdf file in Adobe Reader, it will try to find the associated PDF file, and open it.

FDF is not the only format used for PDF form data. There is also the XML-based XFDF, and a format based on standard Form URL encoding.

Specifications

 * FDF is defined in the PDF specification.

Software

 * Acrobat Forms Data Format (FDF) Toolkit
 * Adobe Reader
 * Adobe Acrobat

Sample files

 * http://docs.appligent.com/fdfmerge/fdfmerge-form-data-format/#The_FDF_file_format - An example of FDF format