Blog
Thoughts on Excel add-ins, Lua scripting, and building xllify.
Functional extensions for Lua
Higher-order functional primitives now built into xllify
Python in Excel is slow. Here's why XLL functions are faster.
Python in Excel runs behind a service with serialization overhead. XLL functions run inside Excel itself, on multiple threads. Here's what that means in practice.
Excel's fastest custom functions are also the hardest to build. xllify changes that.
XLL add-ins are Excel's highest-performance extension mechanism, but Microsoft say they're impractical for most developers. xllify changes that.
Ever wish you could just add a function to Excel?
Adding a truly custom function to Excel used to mean C++, the XLL SDK, and weeks of work. xllify makes it a few minutes' work.
XLL security: what you need to know
XLLs are powerful but come with a trust model worth understanding before you distribute one.
One codebase, two runtimes
How xllify runs the same Lua function code in both a native XLL and an Office Add-in.
How xllify uses Claude to suggest code
How xllify uses Claude models to generate Lua function code inside the Assistant.
Why xllify uses Lua as its scripting language
Lua is tiny, fast, and embeddable by design. It sounds simple, but that simplicity is exactly what makes it a good fit for Excel add-ins.
Hello, world
Introducing xllify - build Excel custom function add-ins in Lua or with AI code assist, no C++ or JS required.