When will {billingPeriodStartDate} and {billingPeriodEndDate} column in Azure cost detail report be generated?

Question

Hello Azure Community,

I'm reaching out in hopes of gaining some clarity on a particular issue we're facing with the Azure Cost Details API. As part of our data pipeline, we utilize this API to meticulously compile billing and usage data on a daily basis, which is integral to our financial analysis and cloud expenditure tracking.

The core of our challenge lies within the generated cost detail reports, specifically concerning the "{billingPeriodStartDate}" and "{billingPeriodEndDate}" columns. To illustrate, when attempting to retrieve the cost detail report for January 2024 on February 6th, 2024, we find that all expected data populates correctly except for the values in the "{billingPeriodStartDate}" and "{billingPeriodEndDate}" columns, which remain null. It's not until roughly mid-February, typically around the 15th (it's just in my experience), that these columns are populated with the data for January, thereby completing the report.

We're seeking clarity on whether there's a predictable schedule for when these columns are populated. Is there a specific timeframe or trigger that ensures these fields are filled, or is the population of these columns expected to occur within a vague period each month?

Any insights, documentation references, or experiences shared regarding this issue would be greatly appreciated. Our goal is to refine our data pipeline to ensure timely and accurate financial reporting, and understanding this aspect of the Azure billing system is crucial.

Thank you in advance for your time and assistance.