PDFTwin

Resources · Updated July 2026

How PDFTwin works

PDFTwin is a hybrid PDF workspace — fast client-side tools for everyday organize and privacy-sensitive work, plus secure server processing for conversions that need real layout engines. Here is exactly what happens to your files.

Open Compare PDF

Hybrid architecture

We split tools by where the work actually belongs. Browser engines (pdf-lib, PDF.js, Tesseract.js) handle merge, split, rotate, compare, sign, remove pages, images-to-PDF, PDF-to-JPG, text extract, and OCR — your files never leave your device. Server-side Python and image pipelines handle PDF → Word/Excel, compress, watermark, lock/unlock, extract pages, and image convert/resize — then discard files immediately.

  • 10 tools run entirely in your browser
  • 8 tools use secure in-memory server processing
  • No permanent file storage on our servers
  • Workspace file tray uses browser IndexedDB on your device

Privacy you can verify

Inspired by transparent client-side tools like ihatepdf and Sejda Desktop, PDFTwin labels every tool with where processing happens. On client-side tools, open DevTools → Network while merging or comparing — you will see no file upload to our origin. Server tools encrypt transfers with HTTPS and delete files after the response completes.

  • Client tools: zero upload bytes to PDFTwin
  • Server tools: in-memory only, discarded after processing
  • We do not use your documents to train AI models
  • Compare PDF renders locally with PDF.js

Free vs Pro — why limits exist

Unlike ad-funded unlimited tools (PDF24) or fully client-side stacks (ihatepdf), PDFTwin pays real server cost for Word/Excel conversion and compression. We keep the free tier generous — no watermarks, unlimited organize tools — and gate heavy server use instead of stamping logos on your exports.

  • Free: 50 MB per file, merge up to 5 PDFs, 3/day PDF → Word or Excel
  • Pro: 200 MB per file, unlimited merge batch and document exports
  • Never: watermarks on free output
  • 18 tools available on both plans

What we do not do (yet)

PDFTwin is a focused web workspace — not a full document platform. We do not offer ISO certification pages, native mobile apps, or enterprise SSO today. We do offer honest limits, a Compare PDF differentiator, and multilingual guides for core workflows.

  • No Chrome extension or desktop app (web-first)
  • No cloud file vault — workspace tray is local to your browser
  • PayPal Pro billing; live checkout when VITE_CHECKOUT_LIVE is enabled
  • See our FAQ for security, billing, and tool-specific questions

Client-side tools

  • Merge & arrange
  • Split PDF
  • Rotate pages
  • Compare PDFs
  • Sign PDF
  • Remove pages
  • Images → PDF
  • PDF → JPG/PNG
  • PDF → text
  • OCR

Server-side tools

  • PDF → Word / Excel
  • Word → PDF
  • Compress PDF
  • Watermark PDF
  • Lock & unlock
  • Extract pages
  • Image convert
  • Resize images