EN ZH

Secure PDF Stamping

PDF SealBox

Add image stamps, cross-page seals, page-specific stamps, rotation, opacity, batch output, and visible signature marks directly in your browser.

Data safety first Default mode keeps files in your browser. Our server does not keep uploaded PDFs.

Private documents?

For contracts, invoices, certificates, legal documents, or files you cannot upload anywhere, use PDF SealBox Desktop for fully offline processing on Windows.

Get Desktop App
Disclaimer

PDF SealBox is a document utility, not legal, financial, or compliance advice. Visible stamps and browser-added signature marks do not automatically create a legally validated digital signature. Always review the output and confirm that it is acceptable for your workflow before using it for contracts, invoices, certificates, filings, or regulated documents.

01

Files & Output

Choose one or more PDFs. Folder mode is supported in browsers that expose directory selection.

02

Stamp Image

Use a transparent PNG or JPG stamp image. Transparent PNG is recommended for clean seals.

Preset stamps

03

Digital Signature

Browser mode can place a visible signature mark. Cryptographic PFX signing requires a server signing service or PDF SealBox Desktop for Windows.

Offline Desktop App

For privacy-sensitive files, use PDF SealBox Desktop and process everything offline on Windows without network upload.

PDF SealBox Desktop

Windows-only desktop app. Requires account login and a one-time $9.9 purchase when the checkout flow is enabled. The purchase flow is prepared for WooCommerce or a membership plugin.

  • Fully offline PDF stamping on Windows only.
  • Supports encrypted output and PFX certificate workflows.
  • Better choice for confidential contracts and internal documents.
$9.9 The paid download entrance is temporarily disabled while the WooCommerce/member payment flow is being prepared.

FAQ

Common questions about browser-based PDF stamping and secure file handling.

Will my PDFs be stored on your server?

The default browser mode processes files locally. If a future server fallback is used, files should be deleted after processing and not retained.

Can it add cross-page stamps?

Yes. Browser mode can split the stamp image across pages and place it on the selected edge.

Does browser mode support true PFX signing?

Not as a pure browser feature. Use a server signing workflow or PDF SealBox Desktop for Windows for certificate-based signing.

Which PDF library is used?

The browser tool uses pdf-lib, a free MIT-licensed JavaScript library, for local PDF modification.