Compare software

Orion Viewer vs Adobe Acrobat Reader: catalog facts
Orion Viewer	Adobe Acrobat Reader
Free Free and open source under the GPL.	Freemium Free to use; editing and conversion require a paid Adobe Acrobat subscription.
Android	Windows, macOS, Android, iOS
Opens DjVu as well as PDF, XPS, CBZ and TIFF Configurable tap zones and key bindings for page turning	Faithful rendering of complex PDFs and forms Form filling, signing and annotation included free
Viewer only, with no PDF editing Interface is functional rather than polished	Frequent prompts to upgrade to paid Acrobat Large install compared with lightweight readers
Downloadable app	Downloadable app
Open source	Closed source
License: GPL-3.0-or-later	License: Proprietary
No account needed	Not stated if an account is needed
Works offline	Works offline
Official website Full listing and sources Checked October 2, 2026	Official website Full listing and sources Checked October 1, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.