Excel Add-in for PDF Comparison

Key Requirements
Add a button in the Excel ribbon (modern Office UI).

On click:

Open a screen to upload two PDF files (old & new versions).

After clicking "Compare":

Show a side-by-side comparison of both files.

Highlight changes (added, removed, modified text/data).

Provide a summary list of all changes.

Allow filtering differences (e.g., show only changed rows).

Option to export comparison results to Excel:

Clicking a cell with differences opens a PDF preview pane with changes highlighted.

Expectations
Clean, modern, user-friendly UI.

Fast and accurate PDF comparison even for large reports.

Support structured PDF reports (tables, rows/columns).

Bonus: Ability to filter by change type.

Technical Requirements
Must be developed in C#.

Deliverables:

Secure signed DLL

MSI installer (no other packaging options accepted)

Source code

Simple user documentation (optional but appreciated)

No alternative tech stacks or packaging formats (e.g., no web add-ins, no ClickOnce).

Timeframe & Budget
4 days 125 Euro maximum !
Prototype (functional UI with dummy data)

Full implementation

Preferred Experience
Proven experience building Excel VSTO Add-ins in C#.

Experience with PDF text & table extraction and comparison (e.g., iTextSharp, PDFSharp, or similar libraries).

If you’ve built a similar PDF comparison or Excel integration tool, please share examples.

Deliverables
Fully working Excel add-in (MSI installer + signed DLL).

Source code (Visual Studio project).

Documentation for installation and usage.