Privacy Policy for NiosPDF (Windows and Mac)

Package identity: SiddharthPattnaik.NiosPDF
Last updated: 4 October 2026
Other platforms: Android · iOS

NiosPDF ("the app") is a PDF viewer and editor for Windows and macOS. This policy explains what the app does and does not do with your information. In short: NiosPDF does not collect, transmit, or sell your personal data, and your documents never leave your computer — unless you choose to connect the optional AI assistant to an AI server of your own (see section 6).

1. Information we collect

We collect no personal information whatsoever. The app has no user accounts, no sign-in, no advertising, no analytics SDK, and no crash-reporting or telemetry SDK. We operate no servers and receive no data from your computer.

Reporting a problem. If the app runs into an error, Settings offers an Email log action. It opens your mail app with a message to the developer (support@spattnaik.in) already written, with the app and system version in the text and the crash log (section 3) attached. Nothing is sent by NiosPDF: you can read, change or delete the message and the attachment, and it goes only if you press Send. You can also share the log yourself or clear it in Settings. We use a report only to fix the problem it describes, and keep it only for as long as that takes.

2. Your documents and files

Every operation — viewing, editing, merging, splitting, annotating, filling and signing forms, compressing, converting between PDF and Office formats, and optical character recognition (OCR) — is performed entirely on your computer. Your documents are never uploaded to us or to any third party.

3. Data stored on your computer

The app stores the following locally, in its own application data folder, so that it can work between sessions. This data stays on your computer and is removed when you uninstall the app or delete that folder:

• A library index of documents you have opened, including file names, paths, page counts and thumbnails.
• A text search index built from documents you choose to index, so search works offline.
• Signatures and form-filling profile details (for example a name, address or email) that you choose to save for reuse when filling and signing documents.
• Recovery copies of in-progress edits, so unsaved work survives a crash or power loss.
• Any OCR language packs you have chosen to install (see section 5).
• If you use the optional AI assistant: the AI models you chose to download; the passages, summaries, suggested questions and conversations it keeps so they open instantly next time; and, if you configured one, your own AI server's address, model name and API key, encrypted with a key held by your operating system's secure credential storage.
• App settings and preferences, such as theme, window layout and default OCR language.
• A crash log: a short technical record of the most recent errors the app could not handle (when each happened and where in the app's code it failed). An error message can occasionally name a file. The log never leaves your computer unless you send or share it (section 1), and you can clear it in Settings.

4. Network use

NiosPDF is offline by design. It makes no network request while you view or edit a document, and it performs no background communication, update check or usage reporting. The app contacts the network only in the situations below, every one of which you start:

• Installing an OCR language pack. If you ask for a Tesseract language that is not yet installed, the app downloads that language's data file directly from the public tesseract-ocr/tessdata_fast repository on GitHub. The request contains nothing but the language code; no document content, identifier or personal data is sent. As with any web request, GitHub receives your IP address and handles it under GitHub's privacy statement.
• Downloading an offline AI model. If you choose a model for the AI assistant, the app downloads that one file from Hugging Face, from the repository that hosts it: Qwen, LM Studio Community, HuggingFaceTB (SmolLM2, the Micro model) or CompendiumLabs (bge-small-en-v1.5, the Lite smart document search model). The request contains nothing but the file's address; Hugging Face receives your IP address and handles it under the Hugging Face privacy policy. Offline models are available on Windows.
• Your own AI server, if you configure one. The text of the documents you ask about, and your questions, are sent to the AI service whose address you entered (section 6).
• Checking for an update (Windows, Microsoft Store version). When the app starts, it asks the Microsoft Store whether a newer version is available and, if so, offers to install it. This is done by the Microsoft Store through the operating system, not by a server of ours; NiosPDF sends no document content, identifier or personal data, and receives only whether an update exists. The check is skipped for copies not installed from the Microsoft Store. Nothing is installed unless you choose Update now, and it is governed by Microsoft's privacy statement.
• Opening a link. When you click a web link — in a document or in the app — the address is handed to your default browser, which does the fetching under its own policy.

5. OCR and text recognition

Text recognition runs entirely on your machine. On Windows the app uses the operating system's built-in Windows Media OCR; on macOS it uses Apple's built-in Vision framework; and optionally it uses Tesseract, an open-source engine bundled with the app. Page images and recognised text are never sent off the device by NiosPDF. The only network activity related to OCR is the language-pack download described in section 4.

6. AI assistant (optional)

NiosPDF includes an optional AI assistant that can summarise a document, answer questions about it with page references, suggest next steps, and explain, simplify or translate selected text. It is off by default, and nothing about it runs, downloads or is sent anywhere until you turn it on in Settings.

• Offline models (Windows). The assistant runs an AI model entirely on your computer. No model is included in the app; the one you choose is downloaded once, as described in section 4. After that, every summary, answer and suggestion is produced on your computer; your documents, questions and answers are not sent to us or to anyone else.
• Your own AI server (Windows and Mac). Instead of an offline model you may enter the address and API key of an AI service of your choosing (for example OpenAI, or Ollama or LM Studio running on your own machine). If you do, the text of the documents you ask about and your questions are sent to that service — over HTTPS, or to your own computer — which handles them under its own terms and privacy policy. NiosPDF asks you to confirm this before the first use, shows the server's address wherever an answer is written, and never sends anything there on its own. We do not operate, see or receive anything from that service.
• Memory. The model is loaded only while you are using the assistant, and is removed from memory when it has been idle for a short while, when the window is minimised, and when the app closes.
• Reporting an answer. The assistant's header has a flag, "Report this answer". It opens your mail app with a message to the developer (support@spattnaik.in) already written: the question you asked and the answer you are reporting (or the summary), which model wrote it, and the app and system version. No document text and no server address is included. Nothing is sent by NiosPDF: the message is in your mail app, you can change or delete any of it, and it goes only if you press Send. If you have no mail app, the same text is copied so you can paste it into one. We read reports to improve the assistant and remove content that should not be produced, and keep them only for as long as that takes.
• Deleting it. You can remove downloaded models, remove your server details, and clear everything the assistant kept, in Settings → AI assistant. Removing a document from the library also removes what the assistant kept about it.

7. Third-party components

The app bundles PDF, document-conversion and UI libraries — including Syncfusion, PdfPig, PDFsharp, Tesseract and the llama.cpp inference engine — all of which run locally and perform no network communication of their own.

8. Files, printing and sharing

• File access. The app reads only the documents you explicitly open, import or drag into it. It does not scan or index your drive on its own.
• File associations. On Windows you may choose to let NiosPDF open PDF files by default. This registers the app with the operating system and involves no data collection.
• Printing. Printing hands the document to your operating system's print system and the printer you select. NiosPDF sends nothing elsewhere.
• Sharing and export. If you export or share a file to another application, that file and its handling then fall under that application's own privacy policy.

9. Store distribution

If you installed NiosPDF from the Microsoft Store or the Mac App Store, that store operates its own account, purchase and diagnostic systems, governed by Microsoft's privacy statement or Apple's privacy policy respectively. NiosPDF does not receive any of that data.

10. Children's privacy

NiosPDF is a general-purpose productivity tool and is not directed at children under 13. Because we collect no personal information from anyone, we do not knowingly collect it from children.

11. Data sharing, sale and retention

We do not share, sell, rent, or disclose personal data, because we do not collect any. There is no server-side retention of your data. Data held locally is retained until you delete it in the app, delete the app's data folder, or uninstall the app.

12. Your rights

You remain in full control of your data. You can delete individual documents, signatures, saved profile details and language packs from within the app, or remove everything at once by deleting the app's data folder or uninstalling the app. Since we hold no copy of your data, there is nothing for us to delete on your behalf.

13. Security

App data is stored in your user account's application data folder, protected by your operating system's normal file permissions. Password-protected PDFs remain protected; passwords you enter are used only to open the document in memory and are not saved unless you choose to. Note that data in a per-user folder is readable by anyone with administrative access to that computer, so treat a shared machine accordingly.

14. Changes to this policy

If this policy changes, the updated version will be published at this same URL with a revised "Last updated" date. Material changes will also be noted in the app's release notes.

15. Contact

Questions about this policy or the app can be sent to sidd.pattnaik@gmail.com.