Privacy Policy for NiosPDF (Android)

Application ID: com.niospdf.app
Last updated: 4 October 2026
Other platforms: iOS · Windows and Mac

NiosPDF ("the app") is a PDF viewer and editor. 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 device — unless you choose to connect the optional AI assistant to an AI server of your own (see section 5).

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 SDK. We operate no servers and receive no data from your device.

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, and optical character recognition (OCR) — is performed entirely on your device. Your PDFs and other files are never uploaded to us or to any third party.

3. Data stored on your device

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

• 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 an interruption.
• 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 the Android Keystore.
• App settings and preferences, such as theme 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, and Android's own record of why the previous session ended). An error message can occasionally name a file. The log never leaves your device unless you send or share it (section 1), and you can clear it in Settings.

4. Permissions the app requests, and why

• Internet / network state — used by the app in two cases you start: downloading an offline AI model you choose in Settings (section 5), and, only if you configure one, sending questions to your own AI server. It is also used by Google Play services to download the on-device machine-learning models described in section 6, and to hand a web link to your browser when you tap one. The app itself does not upload any of your content.
• Camera (optional) — used only when you start the document scanner, to capture pages. Captured images are saved to the app's own storage; they are not transmitted anywhere.
• Foreground service and notifications — used to show progress when a long batch operation (such as OCR over many pages) continues while the app is in the background.
• Access to files you select — the app can only read the documents you explicitly open or import through the system file picker or share sheet.

5. AI assistant (optional)

NiosPDF includes an optional AI assistant that can summarise a document, answer questions about it with page references, suggest next steps (such as filling a form or finding personal data to redact), 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 (the default). The assistant runs an AI model entirely on your device. No model is included in the app: you choose one in Settings and it is downloaded once 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 download request asks for the model file and nothing else — no document content, identifier or personal data is sent. As with any web request, Hugging Face receives your IP address and handles it under the Hugging Face privacy policy. After that, every summary, answer and suggestion is produced on your device; your documents, questions and answers are not sent to us, to Hugging Face, or to anyone else.
• Your own AI server (optional). Instead of an offline model you may enter the address and API key of an AI service of your choosing (for example OpenAI or a server you run yourself). If you do, the text of the documents you ask about and your questions are sent over an encrypted (HTTPS) connection to that service, 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 you leave the app, and when the system is short of memory.
• 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. Downloaded models and your server details are excluded from Android's cloud backups.

6. Third-party components

NiosPDF uses Google ML Kit (Document Scanner and Text Recognition), delivered through Google Play services, for page detection and OCR. Recognition runs on your device; page images and recognised text are not sent to Google by NiosPDF. Google Play services may download the required models over the network and may collect its own operational and diagnostic information under Google's own policies. ML Kit's own usage logging is switched off inside NiosPDF: the usage records it would otherwise upload from the app are discarded on your device. See Google ML Kit terms and the Google Privacy Policy.

NiosPDF uses Google Play's in-app updates library to tell you when a newer version is available. On launch it asks Google Play whether an update exists; NiosPDF sends no document content, identifier or personal data and receives only the update status. If you choose Update now, Google Play downloads and installs it under the Google Privacy Policy. Nothing is installed unless you choose it.

The app also bundles PDF, document-conversion and UI libraries (including Syncfusion, PdfPig and PDFsharp) and the llama.cpp inference engine, all of which run locally and perform no network communication. The AI models are published by the Qwen team (Alibaba Cloud) and Hugging Face (SmolLM2) under the Apache 2.0 licence, and by BAAI (bge-small-en-v1.5) under the MIT licence, and are downloaded from Hugging Face as described in section 5.

7. 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.

8. 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 on your device is retained until you delete it in the app, clear the app's storage, or uninstall the app.

9. Your rights

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

10. Security

App data is stored in Android's private per-application storage, which other apps cannot read. 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.

11. 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.

12. Contact

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