CypherPDF

A clutter-free PDF reader for Android. No ads. No accounts. No tracking. No launcher icon.

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Why this exists

Most "free" PDF apps on the Play Store come with a sign-in wall, a home-screen icon you never asked for, a permission list longer than the app itself, and a tracker phoning home in the background.

CypherPDF doesn't do any of that. You open a PDF from another app (file manager, browser, email, etc.), you read it, you close it. That's the whole app — it has no launcher icon and doesn't appear in your app drawer.

Features

• Continuous scroll — pages flow top to bottom like a real document
• Pinch to zoom, with panning — zoom in and drag around the page freely, no need to zoom back out to reposition
• Tap to focus — tap anywhere to hide the top bar and read distraction-free
• Auto light/dark theme — matches your system theme automatically
• Jump to page — tap the page indicator to type in a page number directly
• Password-protected PDFs — you're prompted for a password if the file needs one
• Share — re-share the currently open PDF to another app
• No internet permission requested — the app has no network code and requests no network access

What it deliberately doesn't do

• No launcher icon / doesn't appear in your app drawer — it opens only when you open a PDF with it
• No accounts, no cloud sync, no analytics, no ads
• No editing, annotation, or form-filling — this is a reader, not an editor

Installing

Download the latest APK from the Actions tab (pick the most recent successful run and grab the CypherPDF artifact), or build it yourself — see below.

Building from source

Requirements: JDK 17, Android SDK (API 34), Gradle 8.9+.

git clone https://github.com/prvthmpcypher/cypherpdf.git
cd cypherpdf
gradle assembleDebug

The debug APK will be at app/build/outputs/apk/debug/app-debug.apk.

CI builds run automatically on every push to main via .github/workflows/build-apk.yml.

Tech stack

• Kotlin, AndroidX (core-ktx, appcompat, material, recyclerview)
• android-pdf-viewer (mhiew fork) for PDF rendering, zoom, and pan
• No Firebase, no Google Play Services, no analytics SDKs

License

GPL-3.0 — see LICENSE.

Contributing

Issues and pull requests are welcome. If you're changing the PDF-rendering path or the icon/manifest, please test both a debug and a release (assembleRelease) build before opening a PR — the release build type runs ProGuard/R8, which behaves differently from debug.

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