PDF Watermark, Page Numbers, Metadata Editor
3-in-1: add watermark, insert page numbers, edit title / author / keywords.
Your PDFs are not uploaded to any server. All processing runs in your browser via pdf-lib (JavaScript library).
Output mode
📖 Compare modes · Detailed explanation (expand)
| Aspect | Vector mode | Image mode |
|---|---|---|
| How it works | pdf-lib drawText (Tm matrix + Tj operator) — PDF standard text object | canvas API raster → PNG embed |
| Preview ↔ PDF position | ~0.4 pt (0.1mm) micro offset | Pixel-perfect match |
| Zoom quality | Infinite (vector) | Sharp up to ~300%, blurry beyond |
| Text search (Ctrl+F) | Yes | No |
| Watermark extraction/removal | Possible (Adobe Acrobat etc.) | Not possible (raster, no text object) |
| Screen reader accessibility | Reads as text | Image — not readable |
| File size impact | +few KB | +tens to hundreds of KB |
| Processing speed | Very fast | Slightly slower (canvas + PNG encode) |
Vector Mode Default
- Pros
- Infinite zoom without pixelation
Ctrl+Fcan search "CONFIDENTIAL" in PDF viewers- Lightweight — minimal size impact even on multi-page PDFs
- Screen reader accessible (good for visually impaired users)
- Cons
- ~0.4pt (0.1mm) position offset vs preview due to typography metric differences — barely visible to the eye
- Watermark text object can be selected and deleted in Adobe Acrobat (weak security)
- Best for
- General business documents, reports, quotes
- Blog / SNS distribution PDFs
- Resumes / portfolios (text search matters)
- Multi-page or large PDFs (file size priority)
Image Mode Precise / Secure
- Pros
- Same typography rendering pipeline as preview → pixel-perfect match
- Watermark is PNG — cannot be extracted, selected, or deleted as text
- Strong stamp impression — good for legal evidence, confidential markings
- Cons
- Antialiasing visible at >300% zoom
- File size +tens to hundreds of KB (one PNG per page size)
- Ctrl+F text search doesn't work
- Screen readers can't read the watermark — WCAG accessibility impact
- Best for
- Contracts, NDAs, legal documents (anti-tamper)
- Design drafts where visual accuracy matters
- Confidential material at risk of competitor exposure
- When watermark must align with specific body content
💡 Decision guide
When in doubt, use Vector (default) — works for most cases. Choose Image when pixel-perfect position with preview matters, or when anti-tamper protection is critical.
Compatibility: Both modes work in all standard PDF viewers (Adobe Acrobat, macOS Preview, Chrome PDF, iOS, Android). Note: Image mode watermarks become searchable indirectly if processed through OCR tools.
Preview — page 1 of the first PDF
Drag the watermark to position
Loading PDF preview…
Position (x · y %): 50% · 50%
Quick position:
0 / 0
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Common use cases
| Situation | Recommended mode |
|---|---|
| Internal document security marking | Watermark "CONFIDENTIAL" |
| Quote / contract draft | Watermark "DRAFT" |
| Resume / portfolio page numbers | Page numbers "1 / N" bottom center |
| Legal documents, evidence | Page numbers "Page 1 of N" + watermark |
| Clean up unknown-author PDF | Metadata → set title / author |
| Standardize company portfolio PDFs | Metadata → unify author as company name |
Related tools
Frequently asked questions
Are my PDFs uploaded?
No. All processing runs in your browser via pdf-lib (JavaScript library).
Is the watermark applied to all pages?
Yes. Every page gets the same watermark. Configurable text, position, rotation, opacity.
Can I customize page number format?
4 formats: 1 / 1 / 10 / Page 1 of 10 / - 1 -. 6 position options.
Why does metadata matter?
Title / author / keywords appear in viewer tabs, search, document management. 'Untitled' or unknown author looks unprofessional.
Can I set a PDF password?
Password encryption is NOT supported (limitation of static-site PDF encryption libraries). Use Adobe Acrobat or a desktop tool.
References
Last verified: 2026-05-10 / pdf-lib (MIT) JavaScript library.
- pdf-lib (MIT) — GitHub
- PDF 1.7 standard — ISO 32000-1
⚠️ Some PDF viewers may show slight position differences after watermark / page numbers. Verified against Adobe Acrobat and Chrome PDF viewer.