How Oxna Works

The big picture of OxnaPDF: what runs on your device, what runs on our servers, and what travels between them.

The Big Picture

Three ways to use OxnaPDF, one principle: your documents are worked on where you are, and only what a task needs ever leaves your device.

Opening, reading and editing a PDF happen on your device. Nothing is sent until you ask AI a question or hand a file to an AI assistant.

Inside the Desktop App

OxnaPDF on Mac, Windows and Linux is built in layers.

• The window shows the interface. It runs sandboxed: the page cannot reach your files or the system by itself.
• The reader draws pages on screen.
• The OxnaPDF engine is our own PDF engine. It runs in background workers, so heavy work never freezes the window. It edits text, redacts, organises pages, compresses and signs. Conversion to Word, Excel and PowerPoint and text recognition in scans (OCR) run in the same background workers.
• The desktop layer opens and saves files, keeps your settings on your computer, and talks to the AI you choose.

• Your original is never changed: OxnaPDF saves a new copy.
• PDF scripts are not run, and XFA forms are switched off, so a PDF cannot run code in the app.
• Opening a PDF from a web address cannot reach addresses on your private network.
• Crafted or damaged files meet size and loop limits, so they are refused instead of freezing the app.

How a Redaction Is Made and Checked

1. You mark the text or area.
2. The engine removes what is under the mark from the page's content, not just covers it.
3. The file is rebuilt without the removed objects.
4. Proof: OxnaPDF reads the new copy back and checks the marked words are gone everywhere: text, hidden strings, unused objects and the pixels under each mark.
5. Only a copy that passes the proof is saved. If it does not pass, nothing is saved and you see why.

How OxnaAI Answers

When you ask OxnaAI:

• your question and the passage you chose go to the OxnaAI service on Cloudflare's network;
• it asks an open AI model running on Cloudflare Workers AI;
• only if Cloudflare cannot answer is the request sent to OpenAI, asked not to store it (OpenAI may keep it for up to 30 days to check for abuse, and does not train on it);
• the answer comes back to your app.

Our service does not log or keep your questions, passages or answers. To share the free daily allowance fairly it keeps only coded forms of a random app number and of your network address, with counters that reset each day.

Working Inside ChatGPT, Claude and Gemini

OxnaPDF connects to AI assistants so they can open, read and change PDFs for you.

• ChatGPT and Claude on the web: the assistant talks to the OxnaPDF connector service on Cloudflare. A PDF you hand it is held in memory, in a container reserved for your account, while you work, and deleted at most 30 minutes after you last use it. It is not written to disk on our servers and not used to train any model.
• Claude Desktop and Claude Code: the OxnaPDF extension runs on your computer, so your files stay there.
• Gemini CLI and Antigravity: an OxnaPDF extension adds the same tools.

Downloads and Updates

• Installers for Mac, Windows and Linux are stored on Cloudflare and listed with SHA-256 checksums on the download page, so you can check a file before you open it.
• The app checks for updates only at our own address and refuses redirects. When there is a new version it opens the download page; nothing installs itself.

Built and Checked Before Each Release

• Our own PDF engine, with regression tests for drawing, editing, redaction and security.
• Security audits with Cloudflare's security-audit method on the desktop app, the website and the services; the medium-severity faults they found were fixed before this release.
• Independent AI reviewers checked code, translations and security (see How Safe).

How Safe · How Private · How Fast · How Free · Compare to Acrobat