How to retrieve historical monthly allocated quota (the custom quota limit in policy) for previous months?

Question

How to retrieve historical monthly allocated quota (the custom quota limit in policy) for previous months?

Ashish Gupta 20

Hi Microsoft Team,

I am working with Azure API Management quotas, and I need to retrieve the custom monthly allocated quota for past months per subscription.

<policies>
    <inbound>
        <base />
        <set-backend-service id="apim-generated-policy" backend-id="dev-backend" />
        <rate-limit-by-key calls="120" renewal-period="60" counter-key="@(context.Subscription?.Key ?? "anonymous")" />
        <choose>
            <when condition="@(context.Subscription?.Name == "SPECIFIC_CUSTOMER'S_SUBSCRIPTION_NAME_HERE")">
                <quota-by-key calls="200000" 
renewal-period="2592000"
 counter-key="@(context.Subscription?.Key ?? "anonymous")" 
first-period-start="2025-08-01T00:00:00Z"
 />
            </when>
            <otherwise>
                <quota-by-key calls="100000" 
renewal-period="2592000"
 counter-key="@(context.Subscription?.Key ?? "anonymous")" 
first-period-start="2025-08-01T00:00:00Z"
 />
            </otherwise>
        </choose>
    </inbound>
    <backend>
        <base />
    </backend>
    <outbound>
        <base />
    </outbound>
    <on-error>
        <base />
    </on-error>
</policies>

What I already know:

The API quota-by-counter-keys (/quotaByCounterKeys?api-version=2024-05-01) returns only the current active quota period (based on periodKey, periodStartTime, periodEndTime).

This endpoint does not return quota details for previous months.

However, using the reports API (/reports/byRequest or /reports/bySubscription), I can still see historical API request logs from earlier months (e.g., October, September, June), depending on APIM log retention.

My requirement:

For each APIM subscription, I want to know:

How many calls were consumed in each past monthly quota cycle, starting from the policy’s first-period-start, (e.g., October, September) month cycle
Essentially, I need historic monthly quota counters, not just logs.

Problem:

quota-by-counter-keys only returns:

{  
  "periodStartTime": "2025-10-31T06:00:00Z",
  "periodEndTime": "2025-11-30T16:00:00Z",
  "value": { "callsCount": 5851 }
}

Even though the subscription has been making calls for many previous months.

Questions:

Is there any API or method in Azure API Management to retrieve historic monthly quota usage per subscription (previous quota cycles), or does APIM only store the current cycle’s quota counter?

If Azure APIM does not store past quota cycles:

Is there any recommended approach to reconstruct per-month quota usage reliably?

Or any API to fetch previous quota start/end boundaries?

Thanks in advance!

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Answer 1

Siva shunmugam Nadessin 3,025 Microsoft External Staff Moderator

Hello Ashish Gupta,

No, Azure API Management does not persist historical quota counters. The quota-by-counter-keys API only returns the current active quota period (with periodStartTime, periodEndTime, and callsCount). There is no built-in API to retrieve previous cycles or historic quota counters this is basically because quota counters are designed for real-time enforcement, not historical reporting. APIM analytics and reports are the only source for historical data.

No direct API exists for historical quota boundaries. The first-period-start attribute in your policy defines the initial cycle start, and subsequent cycles are calculated based on renewal-period. However, APIM does not expose past cycle metadata.

Recommended approach to reconstruct per-month quota usage

Since APIM only stores the current cycle, you need to reconstruct historical usage from logs:

Use the Reports API:

Endpoints like /reports/bySubscription or /reports/byRequest allow filtering by timestamp to get API call counts for any date range.

GET https://management.azure.com/subscriptions/{subId}/resourceGroups/{rg}/providers/Microsoft.ApiManagement/service/{serviceName}/reports/bySubscription?$filter=timestamp ge datetime'2025-09-01T00:00:00' and timestamp le datetime'2025-09-30T23:59:59'&api-version=2024-05-01

This returns aggregated metrics like callCountTotal, bandwidth, etc.

Reference Document:

Reports - List By Subscription - REST API (Azure API Management) | Microsoft Learn

Define monthly windows manually:

Use your policy’s first-period-start and renewal-period (e.g., 2,592,000 seconds ≈ 30 days) to compute cycle boundaries.
Query /reports/bySubscription for each cycle range.

Alternative:

Export APIM logs to Azure Monitor / Log Analytics and run KQL queries for monthly aggregation.

Reference Document:

Monitor Azure API Management | Microsoft Learn

Let us know if you have any questions?

Ashish Gupta 20 Reputation points

2025-11-21T04:42:24.6766667+00:00

Hello Siva,

Thank you for your detailed response. I understand that APIM does not persist historical quota counters and that the quota-by-counter-keys API only provides the current active period.

Given that, I have a follow-up regarding reporting requirements for subscriptions with incremental or varying quotas.

For each subscription, we need to show two values per month:

Monthly allowed quota (as defined in the policy, which may vary month-to-month)

Quota used (actual consumption)

Since APIM only stores the current month’s quota value, reconstructing past months’ allowed quotas accurately is challenging. Could you please advise if there is a recommended approach or best practice to reliably track historical monthly allocated quotas, especially when they vary per subscription?

Thank you for your guidance.
Siva shunmugam Nadessin 3,025 Reputation points Microsoft External Staff Moderator

2025-11-22T08:35:51.2166667+00:00

Hello Ashish Gupta

We have our investigate kindly check.
Siva shunmugam Nadessin 3,025 Reputation points Microsoft External Staff Moderator

2025-11-22T08:38:20.3833333+00:00
Hello Ashish Gupta

To meet your reporting requirement—showing monthly allowed quota and actual usage per subscription—you’ll need an external tracking mechanism because APIM does not provide this natively. Here’s the recommended approach:

Best Practices for Reliable Historical Quota Tracking

1. Persist Policy Snapshots Externally

Why: APIM policies define the allowed quota, but these values can change month-to-month.

How:

Automate extraction of quota configuration from the policy XML whenever changes occur.

Store snapshots in a durable store (e.g., Azure Table Storage, Cosmos DB, or SQL Database) with: Subscription ID, Effective date, Quota limit (calls or bandwidth), Policy version or hash for traceability.

Schedule Monthly Quota Capture

Run a scheduled job (Azure Function, Logic App, or Automation Account) at the start of each month to:

Read current quota values from APIM policies.

Persist them in your reporting database.

This ensures you have a historical record even if quotas vary mid-year.

Track Actual Consumption via Metrics

Use APIM diagnostic logs or Azure Monitor metrics for request counts and bandwidth.

Export these to Log Analytics, Storage, or Event Hub for long-term retention.

Combine these logs with your stored quota snapshots to compute:

Monthly Allowed Quota (from snapshots)

Quota Used (from metrics)

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How to retrieve historical monthly allocated quota (the custom quota limit in policy) for previous months?

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