Open source & Linux alternatives:

https://www.qtrac.eu/diffpdf-foss.html

https://github.com/vslavik/diff-pdf https://vslavik.github.io/diff-pdf/

Looks interesting! Just a heads up as you seem to be a UK registered limited company :

>On business letters, order forms and websites, you must show:

>the company’s registered number >its registered office address >where the company is registered (England and Wales, Scotland or Northern Ireland) >the fact that it’s a limited company (usually by spelling out the company’s full name including ‘Limited’ or ‘Ltd’)

https://www.gov.uk/running-a-limited-company/signs-stationer...

Very nice to have a native Mac app doing this!

A related tool would be a cross-platform product the company I work for creates: i-net PDFC https://www.inetsoftware.de/products/pdf-content-comparer

PDFC compares not only graphical differences but also detects content, columns, etc. We originally created it for ourselves because we weren't happy with any of the PDF comparison tools that were out there.

The black and white mode doesn't look very useful. Check out how Autodesk is visualising changes. They use three colours: blue=only in first pdf, red=only in second pdf, black=in both pdfs.

https://help.autodesk.com/view/BIM360D/ENU/?guid=GUID-08779B...

This technology is useful for many industries.

At PlanGrid, we built a version of this into all of our native platforms as well as into our web app. Allowing people to see what changed between pdf revisions was a priceless tool, even for less sophisticated users in the field.

Rasterization is a must since pdfs otherwise are extremely inconsistent based on how they were generated and post-processed.

Suggestion: When highlighting text, you want to use "multiply" blend mode (a.k.a. subtractive color mixing) instead of opacity. Opacity makes black text lighter/greyish, which is not how physical text markers work, or colored sheets of transparent plastic.

Mac app.

They're looking for more beta testers.

I’m going to check this out. Over the years in university, I accumulated different versions of PDFs with different annotations, because I tested various apps. It is very annoying to merge them manually.

Slightly related, I recently discovered that `less` can read pdf files out of the box. Seems like it is working on Linux but not on macOS.

Any news on a Windows or Linux release?