I am running a version of Azure DevOps and would like to track adoption.
Is it possible to get the number of unique visitors who have logged in / used Azure DevOps in the last 30 days, for instance?
I don't know of a built-in way but here are two hacks:
You can look at https://dev.azure.com/{organization}/_settings/audit
, then set the date range to what you want and manually count.
An automated way of doing that could be to use the ADO REST API and send a Query to get the Audit log, then use a bit of code to tally up the unique users from the response.