About hddn

Why this exists

hddn was created by Linas Jonas Zilinskas, a Lithuania-based Senior Software Engineer.

The idea came from a simple problem: sharing PDF files with AI tools often means uploading sensitive information to third-party services.

Many documents contain names, phone numbers, addresses, financial details, IDs, contracts, or internal information that should not be shared directly. Rewriting or manually removing that information before using tools like ChatGPT or Claude quickly becomes frustrating and time-consuming.

hddn was built to make that process simpler.

How hddn works differently

Instead of uploading PDFs to a remote server, hddn processes files locally in the browser and lets users review redactions before exporting a cleaned PDF. The app can also continue working offline after the required tooling is loaded.

• Browser-based PDF redaction
• No account required
• Review every redaction before export
• Offline-capable workflow after tooling is loaded
• No document upload flow

hddn is intentionally designed as a focused utility: open a PDF, remove sensitive information, export a permanently redacted version, and continue with your workflow.

What hddn is not

hddn is not an enterprise surveillance product, a cloud document room, or security theater wrapped around a hidden upload flow.

It also does not use remote AI services or external document-processing APIs for the core redaction workflow. The product direction is practical, narrow, and review-first.

A practical approach to privacy

Privacy tools often rely on promises that are difficult to verify.

hddn takes a simpler approach:

• Files are processed locally in the browser
• Offline mode can be tested directly
• Users stay in control of what gets redacted

The project is still evolving, but the core principle remains the same: sensitive documents should be handled as locally and transparently as possible.