Hello,

The Column ID is a unique identifier assigned to every column which allows the API to look at a specific column or set of columns. The API needs the Column ID in calls to perform column related actions (for example, delete column and update column) https://smartsheet-platform.github.io/api-docs/?csharp#columns

The Column ID is also needed for other various actions, such as getting cell history: https://smartsheet-platform.github.io/api-docs/?csharp#get-cell-history

I canot find this info anywhere. Do you mind sharing how you found it?