NimboNimbo reads the text of both PDFs and lines it up block by block, then word by word, so you see every insertion and deletion with its page number on each side. It also draws page 1 of each file, page 2 of each file and so on at the same size and compares them pixel by pixel: changes in pictures, layout, stamps or signatures show up in red (only in the original) and green (only in the revised file). Everything is computed in your browser.
How it works
- Drop the original PDF and the revised PDF (or both at once).
- Keep Text changes and Visual differences on, or only one of them.
- Select Compare PDFs, review the changes and download the report.
Supported files
Input: two PDFs. Output: an on-screen comparison and a PDF report.
Up to 400 MB per PDF on a computer, 150 MB on iPhone and iPad. Larger files depend on your device's memory.
When to use it
- Check what the other party changed in a contract before signing it.
- Review the differences between two versions of a report or a quote.
- Make sure a re-exported PDF still looks exactly like the original.
Quality and limitations
- The visual check compares page 1 with page 1, page 2 with page 2, and so on: if pages were inserted, rely on the text comparison.
- Scanned PDFs have no text: only the visual check works for them.
- When documents are very different, changes are listed block by block instead of word by word.
Common issues
- Every page is marked as different.
- A page was probably added or removed near the start, which shifts all the following pages. The text comparison is not affected.
- The text comparison is empty.
- The PDFs are scans (pictures of pages). Use the visual check, or recognize the text first (OCR).
Private by design
This tool runs entirely in your browser with JavaScript. Your file is read and processed on your device and is never uploaded to a server. Closing the tab discards everything.
Frequently asked questions
Are my files uploaded?
No. Both PDFs are read and compared in your browser; nothing leaves your device.
Does it compare formatting?
The text comparison looks at words; the visual check catches changes in layout, fonts, images and colours.
Can I share the result?
Yes. Download the comparison report: a PDF with the summary, every text change and the pages that look different.