Alternatives to OpenScan
Scan paper documents into PDFs with an Android application. The listings below can replace it for an important use case. Each note says what changes if you switch.
The original
OpenScan
Scan paper documents into PDFs with an Android application.
Replacements
Listings that take over the same core job as OpenScan.
Open Note Scanner
Open-source Android scanner for notes and printed documents.
Open Note Scanner is also an open-source Android scanner with no account or cloud and automatic edge detection, though it is rougher and developed intermittently.
Adobe Scan
A free mobile scanner app from Adobe that turns paper documents into searchable PDFs with OCR.
Adobe Scan is free but closed source, runs on Android and iOS, and adds built-in OCR and glare removal; combining files needs paid Acrobat Pro.
Genius Scan
Mobile document scanner with fast edge detection and PDF export.
Genius Scan is closed source on Android and iOS with fast edge detection and on-device processing, while OCR and cloud export need the paid tier.
vFlat Scan
Phone scanner that flattens the curve when photographing book pages.
vFlat Scan flattens curved book pages and removes fingers from edges on Android and iOS, but it is closed source with a subscription for full features.
Scanner Pro
iOS document scanner with OCR and workflow automation.
Scanner Pro is iOS only, so it does not run on Android, and its OCR and automated workflows require a subscription.
NAPS2
Simple document scanning to PDF with built-in OCR.
NAPS2 moves scanning to Windows, macOS and Linux using physical scanners, with built-in OCR producing searchable PDFs, and remains free and open source.
Also worth comparing
These listings name OpenScan as their own alternative, so the relationship runs both ways.
CamScanner
Document scanner app that turns phone photos into cleaned-up, searchable PDFs, with online PDF tools.
OpenScan is a free BSD-licensed Android scanner that turns photographed pages into PDFs, with no desktop or web apps and no mentioned OCR.
Similar software
Related functionality, not a direct replacement.
Tesseract OCR
The open-source OCR engine behind most free text recognition tools.
Papermerge OSS
Self-hosted document archive with OCR, tagging and full-text search.