Xodo

Overview

Xodo is a cross-platform PDF reader and annotation app, notably popular on Android and iOS where it competes with mobile PDF viewers, alongside native desktop apps for Windows, macOS, and Linux. It’s currently owned by Apryse (formerly Kdan Mobile’s PDFTron-based product line), which also sells a separate paid Xodo/PDF Studio editing product for more advanced document manipulation.

Xodo’s reader and annotation app is free to use and closed source; despite sometimes being assumed to be open source because of its free pricing, no source code is published. Its business model separates a free annotation-focused reader from paid tools (Xodo PDF Studio, Apryse’s SDKs) aimed at heavier editing and developer integration.

Key Features

• Cross-platform — Native apps for Windows, macOS, Linux, Android, and iOS, all free
• Annotation tools — Highlighting, freehand drawing, sticky notes, and text markup
• Form filling — Fill in interactive PDF forms
• Merge and organize — Combine, reorder, and manage pages across PDF files
• Cloud storage integration — Open and save files from Google Drive, Dropbox, and OneDrive
• Collaboration — Shared annotation on the same document across devices

Use Cases

• Mobile PDF annotation — Reading and marking up documents on phones and tablets
• Cross-device markup — Annotating a document consistently across desktop and mobile
• Basic form filling — Filling out PDF forms without a paid subscription
• Lightweight page management — Merging or reordering PDF pages without a full editing suite

Who It’s For

Xodo suits people who want a free, easy-to-use PDF reader with solid annotation features across both desktop and mobile, without paying for Acrobat. It’s a weaker fit for anyone who specifically wants their PDF tool to be open source and auditable, since despite the free price, Xodo’s code isn’t published.