Trust Center
hddn is designed so the privacy claim can be tested, not just believed. Load offline tools, disconnect from the internet, refresh the redaction workspace, and redact while offline.
No document uploads
Your PDF is opened and processed by your browser on your device.
Works after tooling is loaded
Load offline tooling once, disconnect, refresh the workspace, and keep using it.
Tool files, not documents
Offline mode stores reusable app and runtime assets, not your PDF or review work.
You decide what is removed
Suggestions are only suggestions. Manual review stays part of the workflow.
How this is possible
hddn is a website, but the redaction workspace can run from your browser cache once offline tools are loaded.
Modern browsers can open files you choose, run application code on your device, use WebAssembly-based runtime assets, and cache tool files for later. That is why the app can inspect and prepare a PDF without sending the document to a document-processing server.
The important idea is simple: the site delivers the tool, then your browser uses it locally without uploading your PDF for processing.
What offline mode saves
Offline mode saves reusable tooling assets so the redaction workspace can reload after you disconnect.
- the redaction workspace
- the PDF engine
- the OCR engine
- selected OCR language data
- fonts
- detection dictionaries
- your PDFs
- extracted text
- page previews
- redaction choices
- manual markings
- exported files
This avoids storing document contents in the offline cache. The cache is for the tool, not for your files.
How to fact-check it yourself
You do not have to take our word for it. You can test the no-upload claim with your own device.
- Open the redaction workspace while you still have internet access.
- Use offline mode to load the local tooling.
- Turn off Wi-Fi, disable cellular data, or enable airplane mode.
- Refresh the redaction workspace.
- Open and process a PDF while your device is disconnected.
The first setup needs internet access because your browser has to download the offline tool files before it can reuse them offline.
What we deliberately do not do
Privacy is easier to trust when the product scope stays narrow.
- no accounts
- no cloud document storage
- no remote AI or document-processing API for core redaction
- no hidden upload step
Limits and honest caveats
Offline mode depends on the same browser, device, and cache where you loaded the tooling. If a browser clears its cache, the tool files may need to be loaded again.
Scanned PDFs may need OCR language data. Load the OCR tools and languages you need before disconnecting.
The website still uses normal hosting and delivery services before offline mode is prepared. Those services can see ordinary web request metadata, but they do not receive your PDF for redaction.
The tool helps find sensitive information, but it cannot guarantee perfect detection. Always review your document before exporting and sharing it.