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Local-first processing

Professional PDF sealing, entirely local.

Open a PDF, choose or generate a seal, set any page ranges, and export. All features are free and the document stays in your browser.

No uploadsLocal PDF engineInstant export
Built for cross-page seals

Precise from preview to export

A focused workflow for positioning one seal continuously across the pages that matter.

SEALLive edge preview
Precision control

See the edge placement before export

Select a seal and the page preview updates immediately. Move the vertical control or switch edges without guessing.

  • Left or right edge placement
  • Continuous page-range control
Multi-page workflow

One seal, distributed across every selected page

The same slice geometry powers the editor preview and exported PDF for consistent results.

  • Preview every selected page
  • Bake seal slices into the downloaded PDF
Upload PDF
Choose seal
Export file
Your browser
Security architecture

Your PDF stays in this browser

Opening, previewing, sealing, and exporting happen locally on your device.

Local PDF engine

PDF parsing, preview, sealing, and export run without uploading your document.

Four clear steps

Workflow

A single path around cross-page sealing.

01

Upload PDF

Choose the one PDF you need to seal.

02

Choose seal

Use the default red seal or upload your PNG/JPG seal image.

03

Set placement

Pick the left or right edge, then all pages or one continuous page range.

04

Export file

Confirm the preview and export with seal slices baked into the PDF.

Free for everyone

All features are free

There are no paid tiers, quotas, or checkout steps.

LumosPDF Browser

Free forever

The complete cross-page sealing workflow, available to everyone.

  • Open one or multiple PDF files
  • Multiple seals or repeated sealing
  • Multiple page ranges such as 1-5 and 6-8
  • Batch-seal PDFs in a folder
  • Generate custom seal artwork
  • Left or right edge placement
  • Export finished PDFs
See what is included for free