The universal markup converter
A PDF processor written in Go
PDFCraft is a free, privacy-focused PDF toolkit
MD/.JSON Document OCR and structured data extraction API
PDF transformation/manipulation program + library
Here are my python scripts written until now
Fast, Nimble PDF Writer for Ruby
Merge images and PDFs to a single PDF
Converts every printable document to PDF, JPG, PNG, TIF and more
A Node queue API for generating PDFs using headless Chrome