Common Bill Format (CBF) File Drop Specs

Expected CBF Drop Format



A folder within the S3 Bucket where your adaptor will write data. This must be a folder and cannot be the root of the S3 Bucket.


Represents an “atom” of billing data which will be added, removed, or updated as a complete unit. Currently it must represent a single month of billing data and be formatted as the first day of a month to the first day of the next month: YYYYMMDD-YYYMMDD. For example, the billing data ID for the month of May 2022 would be: 20220501-20220601.

This limitation on the billing data ID (monthly granularity and specific format) may change in future versions.


This is a unique identifier under which is a complete set of data for this <billing_data_id>. Only one <drop_id> needs to exist. If there is more than one, the “current” drop ID is indicated by the manifest.json. This is useful for versioning. When new data is available for this <billing_data_id> it should be added under a new <drop_id> and the manifest.json updated. The old <drop_id> can then be removed or kept in case it’s necessary to “revert”. To remove all data associated with a <billing_data_id> simply create an empty <drop_id> and point the manifest to that.

Although the <drop_id> may be any unique identifier, the best practice is to use a timestamp formatted to remove any special characters. This makes it easy to see when billing drops were delivered and may be helpful for debugging.

For example, a new billing drop created on May 19, 2022 at 3:45:16PM UTC would have a drop ID of 20220519T154516Z



CloudZero ingests cumulatively for each billing period indicated in a data drop. That is, all data for the time period provided in the <billing_data_id> replaces all existing data in the platform. With that in mind, ensure that your drops contain all the data for a given time period.

If your provider only supplies incremental data drops (e.g., each day you get that day's data, and not previous days), adaptors must include code that copies all of the previous data for the billing period into every data drop. Otherwise, you will lose all previous days in a billing period with each drop made.

Please Note: With this in mind, empty data drops will effectively remove all billing data for the supplied period. An empty drop is one containing a <manifest.json> file that points to a CSV with headers and no rows.


Zero or more gzipped Common Bill Format (CBF) CSV files which contain the data for this <billing_data_id>.


This file includes metadata about the current contents under the <billing_data_id> including the version and pointer to the current <drop_id>. A change to the manifest.json indicates the data under this <billing_data_id> should be re-ingested and completely replace any prior instance of data with the same <billing_data_id>.

Data will not be re-ingested unless the manifest.json is updated.

Manifest File Example

  "version": "1.3.0",

CBF Drop Examples

Here is a simple example for a fake cloud provider “Simple Cloud”. This example may also be downloaded for reference.

Folder Structure

  • simple_cloud/
    • 20220301-20220401/
      • 20220314T100216Z/
        • data_export-0001.csv.gz
      • 20220317T171218Z/
        • data_export-0001.csv.gz
      • manifest.json

simple_cloud is the <root_path> of the Billing Connection. A single billing period is represented with data for the month of March. The <billing_data_id> is 20220301-20220401. The folders under the <billing_data_id> are for different data drops. Each one contains all the data for March at the time it was created. A timestamp is used for the <drop_id> — this is not a requirement, but a useful convention. In this example each “drop” contains only a single gzipped CSV file, however for larger billing drops there may be many files.


The manifest.json file contains:

  "version": "1.3.0",
  "current_drop_id": "20220317T171218Z"

It references the current_drop_id which is 20220317T171218Z. The data under this <drop_id> contains all the data from the billing drop which occurred on March 14th (20220314T100216Z) plus any additional data from between the 14th and 17th. The billing drop from the 14th (20220314T100216Z) is no longer needed, but is kept for historical auditing purposes. If necessary we could “revert” to the prior billing drop (for period represented by the billing data ID 20220301-20220401) by updating the manifest to reference 20220314T100216Z.