Hello @Joshua De Wit (Britehouse) Thank you for asking this question on the Microsoft Q&A platform. Happy to answer any questions you may have!
There is no official announcement from Microsoft regarding the deprecation of the Cost Management APIs in Azure. The Cost Management APIs are still actively being developed and supported by Microsoft. Source link - https://learn.microsoft.com/en-us/azure/cost-management-billing/automate/automation-overview
However, Microsoft has announced that the Consumption API, which is used by the Azure Cost Management API, will be deprecated in favor of the new Usage API. The Usage API provides more granular usage data and is designed to be more efficient and scalable than the Consumption API.
Doc reference: https://learn.microsoft.com/en-us/rest/api/consumption/usage-details/list?view=rest-consumption-2023-05-01&tabs=HTTP
Microsoft has not yet announced a timeline for the deprecation of the Consumption API or the expiration of the Azure Cost Management API. However, they have stated that they will provide at least 12 months' notice before any changes are made to the API.
Hope this answers your question. Please write back if you have any further questions!
If the response helped, do "Accept Answer" and up-vote it