Batch PDF Watermark Tool

Teams that share drafts, certificates or invoices constantly need the same stamp — DRAFT, CONFIDENTIAL, a company name — across dozens of PDFs, and doing it one file at a time is pure drudgery. This project builds a batch PDF watermark tool as a single-file web app: queue any number of PDFs, design the watermark with full typographic control, preview it on the actual pages before committing, and process the entire batch with per-file download links. The watermarking is genuinely implemented — PDFs are parsed and rebuilt in the browser with embedded libraries, text is stamped at the PDF content level (not burned into images), and original page sizes are preserved. Because everything runs client-side, sensitive documents never leave the user's machine — a real privacy argument, not a marketing line.

1. The user drops PDF files into the queue; each is parsed in the browser and its page count and size are listed.
2. The watermark designer sets text, font, size, color, opacity (0–100%), rotation, placement pattern and page scope.
3. A live preview renders the watermark over the first page of the selected document at the chosen settings.
4. On process, the engine iterates the queue: for each PDF it opens every in-scope page and draws the watermark text into the content stream.
5. Tiled mode repeats the stamp in a grid; single mode places one instance per the position preset (center, diagonal, header, footer).
6. Each finished file is offered as a download with its original filename plus a suffix; the log records pages stamped per file.
7. Presets can be saved, renamed and reapplied to future batches without re-entering settings.

Tech stack:

• JavaScript (ES6+)
• pdf.js (rendering/preview)
• pdf-lib (stamping)
• In-browser PDF parsing
• Single-file web app
• LocalStorage presets

• [True batch processing] Queue unlimited PDFs; the engine stamps each file in turn with a progress log and per-file download links at the end.
• [Full watermark design] Text content, font family, size, color, opacity, rotation angle, grid/tiled or single placement, per-page or first-page-only.
• [Live preview] See the watermark on the document's real first page before processing — what you see is what gets stamped.
• [Watermark presets] Save and reuse named presets (e.g. DRAFT diagonal, CONFIDENTIAL footer) across sessions.
• [Client-side PDF engine] Real PDF parsing and generation in the browser; documents never upload anywhere.
• [Page-size preserving] Original page dimensions, content and metadata are preserved; only the watermark layer is added.
• [Sample PDFs included] Three realistic sample documents ship with the demo so the batch workflow is testable immediately.

• Single-file batch watermarking app (working demo)
• 3 realistic sample PDFs for testing
• Watermark preset system with starter presets
• User guide: design, batch runs, presets
• Project report PDF (PDF format internals, content streams, text rendering)
• PPT presentation for final review
• Viva Q&A preparation document

• Text watermarks only — image/logo watermarks are future scope.
• Password-protected or encrypted PDFs cannot be opened by the browser engine.
• Very large PDFs (hundreds of pages) process page-by-page; expect proportionally longer runs.
• Scanned-image PDFs accept watermarks fine, but text underneath remains non-selectable as before.
• Font support is limited to the standard PDF base fonts plus embedded options documented in the guide.
• The tool adds watermarks; it does not remove them (removal would defeat the purpose).