A simple tool that uses Azure Functions for querying Office 365 and Microsoft Azure tenant IDs, ie. Azure AD tenant IDs. For details how this was built see my blog: https://jussiroine.com/2019/02/fun-with-azure-functions-building-a-lookup-tool-for-azure-ad-tenant-ids/
A test version can be accessed here: https://tenantidlookup.azurewebsites.net/api/TenantIDLookup?tenantName=foo