But users of PDF.js soon request more than basic PDF viewing; they want features such as annotations, signatures, and form filling ubiquitous today but not supported by or out of scope of the PDF.js project.
Implementing these features in-house often proves time-consuming and complicated. Therefore, to lend developers a helping hand in achieving their short-term requirements, we built a commercial solution over top PDF.js to provide these features out of the box to speed up development and reduce maintenance costs.
That solution, PDF.js Express, wraps a modern React UI around the PDF.js rendering engine to enable PDF annotations, form filling, and signing inside a web app. We’ve also made improvements to the PDF.js engine to enhance text search accuracy and image quality at higher zoom factors for an improved UX, while adding support for real-time document collaboration features, so PDF.js can be quickly integrated within a modern PDF collaboration workflow for common use-cases such as approvals on PDF. To see it in action watch the PDF.js Express overview video.
Lastly, we added an easy upgrade path to our commercial-grade PDF SDK for when user document file format, UX, platform, and feature requirements evolve. Switching to PDFTron from PDF.js Express requires only 1 line of code -- no lengthy migrations. And any UI customizations will continue to work.