Calkin
Excel add-in in C# and .NET
Abelian Group AB (Calkin) • Nov 2025 – Present • Full Stack Developer
Calkin is an Excel add-in that documents workbooks and shows how formulas depend on each other, so finance teams and consultants can find errors in large models faster. I work on the add-in in C# and .NET, and on the tracking and marketing setup around the product.
- C#
- .NET
- Excel VSTO
- Excel COM API
- Server-side tracking
- Analytics
Context
- Customers open big, complex workbooks, and the add-in has to stay fast while it reads them.
- Excel's COM API gets slow and quirky when you call it a lot, so performance needs constant attention.
- Product and marketing decisions depend on tracking data that can be trusted.
What I did
- Build and maintain features in the VSTO add-in.
- Find and fix bottlenecks in how the add-in talks to Excel through the COM API.
- Work on the tracking and marketing tooling the team uses for product and growth decisions.
