Secure Watermarked Document Streaming

I already run a SaaS application that lets me send files with revocable access, but the moment a recipient hits “download” all practical control disappears. I now want the experience to be view-only: the document should stream inside the browser (or an in-app viewer), never land on the user’s disk, and carry an irreversible watermark.

Scope of the upgrade
• Target file types: PDF, DOCX and TXT.
• Delivery method: streaming / in-browser rendering only—no native download option, no “Save as” in the viewer context menu, and nothing written to the temporary downloads folder.
• Watermark: permanently burned into every page or frame, showing the user’s identifying data and a live timestamp so each session leaves a unique forensic trail. The overlay must survive screenshots and basic conversion attempts.
• Existing permissions model must stay intact, so I can still revoke access instantly from the admin console.

What I expect from you
1. Extend the current codebase so any newly uploaded document is processed into a streamable format with the watermark applied server-side.
2. Build or integrate a lightweight HTML5 viewer that renders PDFs, Word docs and text files smoothly, handles zoom/search, and works on desktop and mobile browsers.
3. Keep latency and quality respectable—even large PDFs should open quickly.
4. Provide clean, well-commented code and a short deployment guide so my team can maintain it.
5. the current stack is Next.js + React + Tailwind stack using Supabase and deployed on Vercel

Acceptance criteria
• Attempting to download, print or “inspect element” exposes only the watermarked stream, never the raw file.
• The watermark clearly displays the active user’s name/email and the exact timestamp on every page.
• Revoking access instantly breaks the viewer session.

If you have experience with secure document viewers, DRM, or dynamic watermarking, I’d love to see relevant links or demos in your proposal.