Produced by iText
iText’s Reading and Updating PDF Syntax (RUPS) tool is built on iText 7 Core and offers a crystal-clear look on how a PDF is constructed and makes it possible to inspect the PDF Syntax for possible errors..
If you ever wondered what a PDF looks like on the inside and were scared away when opening a file in a plain text editor, try iText RUPS and many secrets will be unveiled.
RUPS is a PDF inspection tool, which we use a lot internally to inspect PDFs received from customers and users. RUPS immediately updates PDFs as well.