Compare software

Orion Viewer vs Secure PDF Viewer: catalog facts
Orion Viewer	Secure PDF Viewer
Free Free and open source under the GPL.	Free Free and open source under the MIT and Apache-2.0 licenses.
Android	Android
Opens DjVu as well as PDF, XPS, CBZ and TIFF Configurable tap zones and key bindings for page turning	Requires no app permissions Uses a sandboxed WebView to display PDF streams
Viewer only, with no PDF editing Interface is functional rather than polished	Android only
Downloadable app	Downloadable app
Open source	Open source
License: GPL-3.0-or-later	License: MIT AND Apache-2.0
No account needed	Not stated if an account is needed
Works offline	Not stated if it works offline
Official website Full listing and sources Checked October 2, 2026	Official website Full listing and sources Checked October 8, 2026

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