Local PDF editor vs cloud PDF editor
When you edit a PDF online, your file is usually uploaded to a server. A local PDF editor works differently: the file stays on your device and is processed in your browser. Here is what that means in practice.
How a cloud PDF editor works
How a local PDF editor works
When does it matter?
For casual documents like flyers or public brochures, the difference may be minimal. For contracts, financial statements, legal filings, medical forms, personal ID documents, HR records, or anything covered by confidentiality obligations, a local editor reduces exposure by keeping the file under your control.
What you give up with local editing
Local editors depend on your browser's capabilities. Very large files (over 100MB) may be slower to process. Collaboration features like real-time co-editing are not available. OCR for scanned documents may require a server-side component. For most standard PDF editing, conversion, and organization tasks, local processing handles the workload without issues.
MendPDF's approach
MendPDF uses a compiled PDFium-based WebAssembly engine that runs locally in your browser. Core tools including text editing, PDF-to-Word conversion, merge, split, compress, protect, unlock, watermark, and page numbers all process locally. The one exception is Magic Scan, which uses an encrypted relay for phone-to-desktop transfers with automatic deletion after 60 seconds.
Relevant tools
Try a local PDF editor
No upload. No server. See the difference for yourself.