Best PDF Annotators for Linux

Apryse (formerly PDFTron) powers the future of document technology. We help businesses, developers, and enterprises handle documents with unmatched speed, accuracy, and security. Whether running in secure server environments or delivering seamless web-based experiences, Apryse makes document workflows smarter and easier. With Apryse, you can: Embed powerful document features directly into your apps — from viewing and editing to collaboration and compliance. Run at enterprise scale on secure server infrastructure, ensuring reliability without cloud dependencies. Deliver seamless in-browser document experiences with responsive, accessible, and feature-rich web capabilities. Trusted globally, Apryse empowers organizations to simplify operations, enhance productivity, and create exceptional document experiences.

Nutrient SDK brings in-app PDF annotation and markup to document review, so users mark it up where it lives instead of exporting files to a separate review tool. Developers, product managers, and document review teams use it for contract and compliance review, board packs, blueprint and engineering markup, and approval workflows. It offers more than 15 spec-compliant annotation types, including highlights, underlines, strikeouts, ink, shapes, stamps, sticky notes, and free text, that render consistently across web, mobile, and desktop. Threaded comments attach to annotations, record author and time, and can be resolved or reopened, while permissions control who can view, comment on, or edit annotations. Teams can customize colors, toolbars, and stamps, query and manage annotations through the API, and export to XFDF for other PDF tools or Instant JSON for syncing across users and devices.