Cost / License
- Free
- Open Source
Application typeApplication types
Platforms
- Android



Sites and apps similar to PDFkoi include SumatraPDF, which is free and open source. Other options are Okular, Foxit PDF Reader, Xournal++ and PDFgear. PDF Readers like PDFkoi are a crowded field, with more than 50 alternatives for Windows, Mac, Linux, Android and iPhone.



Optical recognition software boasting unmatched text accuracy converts scanned documents to editable Word, Excel, or searchable PDFs while preserving layout. Supports 190 languages, simplifies processes with automated tasks, and includes PDF editing tools.




Sioyek is a PDF viewer with minimal interface optimized for reading research papers and technical books.




Native macOS app for viewing, annotating, and editing images and PDFs, featuring tools for cropping, rotating, resizing images, rearranging pages, full-screen viewing, markup, document merging, batch conversion, and export in multiple formats.




PDF viewer for macOS supports scientific papers, annotations, highlights, bookmarks, split view, exporting notes, AppleScript, multiple annotation types, bibliography integration, full-screen, search, and compatibility with various macOS versions.

Create, Convert, Review and Edit PDF Documents on Windows, macOS, and Linux.




Xodo is the ultimate cross-platform PDF viewer and annotator. Powerful, fast, and optimized for all phones and tablets, Xodo makes it easy to access, edit, share, sync, manage, sign, and more.




Simple Android PDF viewer based on pdf.js and content providers. The app doesn't require any permissions.



A document viewer for the GNOME desktop. You can view, search or annotate documents in many different formats.


Document Viewer is a highly customizable document viewer for Android, fork of the last GPL version of EBookDroid .


PdfDing is a browser based PDF manager, viewer and editor that you can host yourself. It offers a seamless user experience on multiple devices. It's designed be to be minimal, fast, and easy to set up using Docker.

Open-source PDF viewer and editor using Qt framework, featuring hardware-accelerated rendering, encryption, multithreading, text-to-speech, annotation tools, form filling, high-res monitor support, document compression, audio book conversion, and signature validation.

