Working at PDFTron Systems, creators of:

PDF.Online free online document tools.

Xodo a completely free all-in-one PDF reader and PDF annotator/editor for mobile and web.

PDFTron PDFNet a cross-platform PDF & Office SDK

PDF.js Express a modern & commercially supported PDF.js wrapper, with annotations, form filling, and e-signatures.

Web to PDF Converter to easily create beautiful PDFs using your favorite Javascript and CSS framework!