Compare PDF

Spot the difference.

Side by side.

Original

Drop original PDF

or tap to browse

Revised

Drop revised PDF

or tap to browse

No upload
Works offline
No idea what's in your files

Need to compare documents offline? The offline bundle works without a browser or internet connection. $99 once.

Get Bundle →
// How it works

Three steps. Zero uploads.

01
Drop
Drag your original and revised PDFs onto the page. Both stay on your device.
02
Compare
View side by side, overlay, or pixel-level diff. Navigate page by page to see exactly what changed.
03
Download
Save the diff as a PNG. Nothing was ever uploaded.
// Why this is different

Your documents never leave your machine.

Most online PDF comparison tools upload both documents to a server, diff them there, and send back the result. Your confidential revisions pass through infrastructure you don’t control — for a task your own browser can handle.

fwip works differently. The comparison engine runs entirely in your browser. Your PDF is read from your device, processed on your CPU, and the result is saved back to your device. No server is involved. We literally cannot see your file.

No server processing

Everything runs on your device using WebAssembly. Your file never touches a network.

No account required

Drop a file. Get a result. No sign-up, no email, no password.

No subscription

Free in the browser. $99 once for the offline bundle. That's it. Forever.

Works offline

The desktop version works with no internet connection at all.

// Questions

Frequently asked.

How do I compare two PDFs side by side?▾
Drop both PDFs onto fwip — the original and the revised version. The tool renders them side by side with pixel-level diff highlighting. Everything runs in your browser with no upload.
Can I compare PDFs without uploading them?▾
Yes. fwip renders both documents locally using pdfjs-dist and computes the visual diff entirely in your browser. Neither file ever leaves your device.
What view modes are available for PDF comparison?▾
fwip offers three modes: side-by-side, overlay (semi-transparent layering), and diff (pixel-level change highlighting). You can switch between them on any page.
Can I save the PDF diff as an image?▾
Yes. In diff view, fwip provides a button to save the current page’s diff as a PNG image. This is useful for sharing specific changes with colleagues.
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