Is Flatten to Image PDF private by default?

Processing is entirely local. PDF.js renders pages in a canvas element, the canvas exports as PNG or JPEG, and pdf-lib builds a new PDF from those images. No bytes leave your browser at any step.

What this does not protect

• Text becomes non-selectable. Recipients cannot copy-paste, search, or index the text. If they need searchable text, they would need to OCR the result.
• Output file size is almost always larger than the original for text-heavy documents. A 500KB text PDF may become 3-5MB after flatten at 150 DPI.
• 200-page cap exists because each page requires ~50-100MB of RAM for canvas rendering. For longer documents, split first and flatten sections.
• Transparent elements and blend modes may render differently than in specialized PDF viewers. Always verify the output.
• It cannot fix compromised devices, accounts, or unsafe sharing channels.