A privacy-first, free and open-source document scanner.
Scan documents with your camera, auto-crop and dewarp them, and export a PDF — all on-device. No accounts, no cloud, no tracking.
Grab app-arm64-v8a-release.apk from the release's assets — that's the
right build for virtually every phone from the last ~7 years. Prefer a
32-bit or x86 device? Use armeabi-v7a or x86_64 instead.
Captured from the Android build.
- Real document scanning, not just a photo: automatic edge detection with a draggable corner overlay to fine-tune it, then perspective correction (dewarping) into a flat, upright page
- Scan filters — Original, Auto-Enhance, Grayscale, and Black & White — with live thumbnail previews before you confirm
- Re-edit any page after the fact (corners, filter, rotation, brightness, and contrast) without re-scanning
- Capture multiple pages in sequence and reorder them with drag-and-drop
- Automatically restore an unfinished draft after a native app restart
- Import existing photos from your gallery instead of (or alongside) capturing new ones
- Combine captured pages into a single PDF
- On Android, export a searchable PDF with selectable, copyable text using bundled Latin-script OCR; iOS exports image-only PDFs
- Share the PDF via the OS share sheet
- Material 3 UI that follows the system's light/dark theme
- No accounts, no cloud storage, no tracking
- An in-app About screen (the ⓘ icon) shows the exact running version and links straight to this source repo
FOSScanner supports Android and iOS. Edge detection, perspective correction,
and filters run on real OpenCV (opencv_dart) on both mobile platforms.
- All image processing and PDF generation happens on-device.
- Android searchable PDF recognition uses a bundled, offline Latin-script Tesseract model; no OCR text or images are sent over the network.
- Imported gallery originals are never modified or deleted. App-owned camera temp files are removed after the app attempts to copy their bytes into memory (including failed reads).
- Unfinished drafts are saved automatically in the app's private, OS-managed application cache. They survive normal process death and app restarts, but caches are transient and can be purged by the OS under storage pressure; they are not durable storage or included in Android OS backups. A draft includes both original and processed page images plus crop/filter/edit settings. Atomic staging plus one backup generation can retain the current and immediately previous draft contents. Draft data is also removed when you confirm Clear all, choose Clear draft after sharing, clear the app's storage, or uninstall the app. Sharing does not delete a draft unless you explicitly choose that option.
- PDF sharing starts from in-memory bytes. Depending on the platform,
share_plusmay materialize a copy in the app/OS cache for the receiving app; that cache is OS-managed and is not guaranteed to disappear immediately after the share sheet closes. - The app makes no network requests of its own.
Requires Flutter >=3.44.0 with Dart >=3.12.0 <4.0.0 (matching the
locked dependency resolution and pubspec.yaml).
flutter pub get
flutter run| Command | Purpose |
|---|---|
flutter analyze |
Static analysis / lint |
flutter test |
Run the test suite |
flutter build apk --release --split-per-abi |
Build signed, per-ABI release APKs (requires android/key.properties) |
flutter build ios --no-codesign |
Build the iOS app (on macOS) |
docker-compose.yml provides an Android APK build service using the pinned
Flutter 3.44.0 container image, so you don't need the Flutter/Android SDKs
installed locally. The APK service uses the image's x86_64 Android SDK/NDK toolchain;
Docker Desktop uses emulation automatically on Apple Silicon, so that build is
slower there. Native arm64 Linux Docker engines need amd64 emulation (for
example, binfmt/QEMU) for the APK service:
# Debug Android APKs (one per ABI), output to ./docker-output/
docker compose run --rm build-apkIssues and pull requests for Android and iOS are welcome — see CONTRIBUTING.md for the dev workflow and commit message conventions.
FOSScanner is licensed under the GNU General Public License v3.0.