CODEX
An offline-first Android document suite: PDF reader and editor, camera scanner, OCR, forms, signatures, and Word/Markdown/EPUB reading. No ads, accounts, subscriptions, or internet permission.
Off the Rails — 2026CODEX is a private document workspace for Android. It opens PDFs, images, Word files, Markdown, HTML, RTF, ODT, and EPUB; scans paper with automatic edge detection and perspective correction; runs OCR on-device; fills and flattens forms; adds highlights, ink, notes, and signatures; and edits pages with merge, split, extract, rotate, crop, reorder, watermark, password protection, and page numbers.
The app requests exactly one runtime permission - camera - and no internet permission, so the files cannot leave the device. The free tier is a complete reader/editor. Pro is a one-time unlock, not a subscription. The release build has no ads, no account, and no telemetry.
It is currently in release preparation: the Android app is built and signed, and the Play Store listing and billing integration are the next step.
The brief
Most mobile PDF tools are cloud services with subscriptions, ads, or an upload step. The goal was a document suite that works on a plane, in a basement, or on a job site with no signal - and never asks someone to trust a server with a contract or a scan.
The approach
Keep the document engine on-device: pdfium for rendering and text, PDFBox for authoring and page surgery, CameraX for capture, ML Kit for Latin OCR, and a custom scanner pipeline for edges and perspective. Keep annotations in normalized page coordinates so they survive zoom, rotation, and re-render. Make Pro a local entitlement with an offline license key; no account, no server.
The outcome
A complete offline document tool with a real free tier and a one-time Pro unlock. The app is built and signed; the Play Store listing and billing integration are the next step.
0
ads, accounts, or internet permission
1x
Pro unlock, not a subscription
Offline
scan, OCR, edit, read
Next project
INDEX
Have a brief like this?
Bring us the messy version. We are good with messy.