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ReadEraOrion Viewer
Free

Free to download and use without ads, according to the developer.

 Free

Free and open source under the GPL.

Android, iOS Android
  • Opens EPUB, MOBI, PDF, DjVu, Word, FB2 and comic files
  • Reads books directly from ZIP and RAR archives
  • Opens DjVu as well as PDF, XPS, CBZ and TIFF
  • Configurable tap zones and key bindings for page turning
  • Closed source
  • Mobile only, with no desktop version
  • Viewer only, with no PDF editing
  • Interface is functional rather than polished
Downloadable app Downloadable app
Closed source Open source
License not stated License: GPL-3.0-or-later
No account needed No account needed
Not stated if it works offline Works offline

Checked September 23, 2026

Checked October 2, 2026

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