We did announce (but not yet release) custom Azure Machine Learning functions in Excel. I mention in the blog that since Python runs on Azure ML, you'll be able

We did announce (but not yet release) custom Azure Machine Learning functions in Excel. I mention in the blog that since Python runs on Azure ML, you'll be able to run custom Python functions in the cloud, as part of Excel formulas[1]. That announced Azure ML feature is optimized for machine learning models (in terms of the tools/deployment/runtime we've provided), so even though it will work for any Python functions it might not be exactly what you're asking for. Also, depending on your specific use case, you may or may not need client-side execution (Azure ML functions run in the cloud today). I can't share specifics on other unannounced features, but Azure ML functions are only our first foray in this space: we think custom functions running in the cloud are very important for many different use cases in Excel. Also, note that on the JavaScript side, the language choice isn't something new for Excel or Office: for example, there's a public ecosystem of add-ins that automate Excel via JavaScript today[2]. Custom functions are just the latest way we've enabled for extending Excel as part of an add-in[3]. [1] https://dev.office.com/blogs/azure-machine-learning-javascript-custom-functions-and-power-bi-custom-visuals-further-expand-developers-capabilities-with-excel https://dev.office.com/blogs/azure-machine-learning-javascri... [2] https://appsource.microsoft.com/en-us/marketplace/apps?product=office%3Bexcel&page=1 https://appsource.microsoft.com/en-us/marketplace/apps?produ... [3] https://docs.microsoft.com/en-us/office/dev/add-ins/excel/excel-add-ins-overview https://docs.microsoft.com/en-us/office/dev/add-ins/excel/ex...