🔐 Client‑Side PDF Comparison: How It Works & Why It’s Secure

Traditional diff tools require uploading documents to a server, exposing sensitive revisions. Our tool performs all comparison entirely inside your browser using PDF.js to render pages, and canvas pixel analysis to detect differences. No data ever leaves your device — every page is rendered locally and compared pixel by pixel.

We extract each page of both PDFs as images at the same scale, then calculate the difference between corresponding pixels. You can adjust the tolerance threshold to ignore minor variations (e.g., anti‑aliasing). Differences are highlighted in red, making changes immediately visible. Because everything runs client‑side, your documents remain private — ideal for legal, financial, or any sensitive version comparisons.

📘 How to Compare PDFs in 5 Simple Steps

1. Upload PDF A – Drag & drop the original document or click “Browse”.
2. Upload PDF B – Drag & drop the revised document.
3. Navigate pages – Use the Prev/Next buttons to select a page to compare.
4. Adjust threshold – Set the difference sensitivity (lower = stricter).
5. Compare – Click “Compare Current Page”. Differences will be highlighted in red on the diff view or shown side‑by‑side.

No registration, no uploads, unlimited comparisons — all with maximum privacy.

💼 Perfect for Professionals & Everyday Users

Legal Professionals: Spot changes in contract versions. Editors & Writers: Compare manuscript revisions. Designers: Check layout changes between PDF exports. Students: Compare lecture notes or assignment drafts. Business Teams: Verify updates in reports or presentations. Because everything happens locally, you can compare sensitive documents without risking exposure.

❓ Advanced Technical FAQ