Bring your Lua and Python functions to Microsoft Excel
xllify is a packaging tool and runtime that allows you to write high-performance functions for Microsoft Excel in Lua and Python.
$
xllify MyFunctionsAddin.xll
finance.luau trading.py
✓ Built MyFunctionsAddin.xll (2.4 MB) in 0.6s
Write code
Create functions in Lua or Python with your favourite editor or IDE
Run xllify
Build your XLL in seconds with a single command
Install
Load your add-in into Excel to start using your functions
Supported languages
Multiple scripting languages are supported for deployment to Microsoft Excel on Windows.
Lua
xllify embeds a variant of Lua called Luau for safe, close to the metal integration with Excel. Your code is safely sandboxed with no access to the host computer. Luau has very strong numerical performance and is used by millions in Roblox and other well-known games.
- Your Lua functions are embedded as bytecode and sandboxed (no file system access and users can't easily view your code)
- Maximum performance (runs at native speeds)
- Ideal for pure computations and simple async operations
- True multithreaded recalculation
- Statistical functions in the xllify standard library, maybe Pandas is overkill for some use cases!
xllify.fn({ name = "xllify.Hello" },
function(name)
return "Hello, " .. name .. "!"
end)Python (preview)
Python is the defacto choice for data analysis and machine learning. Python processes run externally and communicate with Excel efficiently through named pipes and shared memory. Repurpose your existing, tried and tested code in a few minutes.
- Full system access without sandboxing restrictions
- Use any Python library (pandas, numpy, duckdb, requests...)
- Ideal for data analysis, machine learning and calling out to APIs
- Keeping your code private from end-users isn't required
- Load balancing across multiple processes to make use of multiple cores
@xllify.fn("xllipy.Hello")
def hello(name: str) -> str:
return f"Hello, {name}!"
Both Lua and Python deliver the performance needed for large,
mission-critical workbooks.
5000 calls to Python takes ~40ms and 5000 calls to Lua takes just
8.5ms, on an everyday laptop CPU (AMD Ryzen 5 5500U).
Give it a try →
Why custom functions?
Excel formulas aren't maintainable at scale. They're not reusable and it's easy to create a mess when they're duplicated.
Custom functions allow you to express logic and calculations as code. There are several ways to add custom functions to Excel, each with their own trade-offs.
- Built-in Microsoft solutions: VBA is single-threaded and doesn't fit modern workflows; Office.js works well for many scenarios but can have performance limitations; Python in Excel runs your code in the cloud over a network connection and targets different use cases; the Excel C SDK delivers maximum performance, but is notoriously difficult to use correctly
- Excel-DNA, PyXLL and xlwings are excellent, mature tools that excel in different scenarios. Excel-DNA is .NET-focused and free for commercial use. PyXLL and xlwings offer strong Python integration with per-developer or runtime licensing models suited to enterprise deployments.
How is xllify different?
Built from experience witnessing the common pain points developers and analysts face when developing custom functions, xllify is a focused tool with these goals:
- allow analysts and developers to use scripting languages
- be efficient and very fast
- have simple deployment and licensing
Your scripts get packaged into a single .xll file that's easy to deploy and manage. Licensing is per-XLL, not per-seat. You can distribute each XLL to unlimited users with no ongoing costs, ideal if you are an independent developer shipping a tool, a consultancy developing client solutions, or a business rolling out to thousands of users.
xllify is currently free for all users during beta and will always be free for individuals. Email alex@xllify.com to arrange a demo.