Sign & Stamp PDF
Stamp PDF documents with red seals and signatures in your browser. Advanced red-ink extraction, multi-layer stamps, and corner placement — private, no upload.
- Free
- No Signup
- No Daily Limit
- Browser-Based
- No Server Upload
- Fast Processing
- Works on Mobile
Choose your workflow
Pick company seal or personal signature before uploading a PDF.
Select a workflow above to begin.
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How to stamp a PDF with red seals
Upload the PDF you need to stamp. Add photos of your round seal, title stamp, and signature — the tool removes paper backgrounds using red-ink extraction. Drag layers to align them, pick bottom-left or bottom-right placement, and choose the last page or all pages. Click Stamp PDF to embed the composite seal and download the file.
Everything runs locally in your browser. Contracts and company documents never leave your device.
Why choose SnapKit? Our tools are 100% Private, No Server Upload, Instant Browser-Based, with No File Size Limit.
When should you use this tool?
Stamp PDF documents with red seals and signatures in your browser. Advanced red-ink extraction, multi-layer stamps, and corner placement — private, no upload.
Is my data uploaded to the server?
No. SnapKit processes your files entirely in your browser using client-side WebAssembly, Canvas, and Web APIs. Your documents, images, and audio never leave your device, and we do not store uploads on our servers.
Why choose SnapKit?
Every tool is built around four promises: privacy, speed, freedom, and accessibility. No cloud pipeline — just your browser and your files.
100% Private — No Server Upload
Files are processed on your device with client-side WebAssembly and Canvas. No bytes are sent to our servers.
Instant Browser-Based speed
Skip slow uploads and downloads. Your CPU and GPU do the work locally for near-instant results.
No File Size Limit — Free forever
No registration walls, no watermarks, and no arbitrary caps. Use ringtone, video, PDF, and image tools freely.
Works on every device
iPhone, Android, Windows, and Mac browsers are all supported with the same private, instant experience.
Frequently asked questions
How does red-ink extraction work?
The tool scans each pixel and keeps strong red ink while making paper backgrounds fully transparent — even gray or yellow tinted scans.
Can I stamp every page of a PDF?
Yes. Choose last page only for signature blocks or all pages for document-wide seals.
Is PDF stamping free and private?
Yes. Stamping is free with no account. Files are processed entirely in your browser with zero server upload.
Is my data safe with this tool?
Yes. All processing runs 100% on your device using client-side WebAssembly, Canvas API, and browser APIs. No bytes from your files are transmitted to our servers — zero server upload, absolute privacy.
Why is the processing speed so fast?
Because your file never leaves your browser. SnapKit uses WebAssembly and Canvas to harness your device CPU and GPU directly, skipping slow network upload and download steps.