The PDF::Reader library implements a PDF parser conforming as much as possible to the PDF specification from Adobe

HexaPDF is a pure Ruby library with an accompanying application for working with PDF files. In short, it allows creating new PDF files, manipulating existing PDF files, merging multiple PDF files into one, extracting meta information, text, images and files from PDF files, securing PDF files by encrypting them and optimizing PDF files for smaller file size or other criteria. HexaPDF was designed with ease of use and performance in mind. It uses lazy loading and lazy computing when possible and tries to produce small PDF files by default.

Origami is a pure Ruby library to parse, modify and generate PDF documents.

Ruby/Poppler is a Ruby binding of poppler-glib.

Wraps the pdfinfo command line tool to provide a hash of metadata

Get metadata about PDFs and extract full-quality images. Wrapper around `pdfimages` and `pdfinfo`.