Sales reps use the HubSpot product throughout the day to make phone calls to prospects.

We've found that certain customers using HubSpot have a large number of sales reps concurrently making calls with HubSpot, and this puts heavy load on our systems. In response to this, we'd like to bill our customers based on their peak calling load. In other words, we'd like to bill customers based on their maximum number of concurrent calls.
Each call looks something like this:

{
"customerId": 123,
"callId": "2c269d25-deb9-42cf-927c-543112f7a76b",
"startTimestamp": 1707314726000,
"endTimestamp": 1707317769000
}

The POST body must be in the following format:

{
"results": [
{
"customerId": 123,
"date": "2024-02-07",
"maxConcurrentCalls": 1,
"timestamp": 1707314726000,
"callIds": [
"2c269d25-deb9-42cf-927c-543112f7a76b"
]
}
]
}