API Gateway supports core as well as transaction-based licensing model. When API Gateway uses a transaction-based licensing model, then each service invocation is considered as a transaction and API Gateway keeps a track of these transactions. API Gateway transactions for the current month is compared with the maximum number of transactions allowed in a month. The maximum number of transactions that are allowed in a month is specified by the license agreement as represented in the licenseKey.xml file available in the InstallDir\IntegrationServer\instances\instance_name\config directory.

When the calculated transaction count is higher than the maximum transactions allowed per month, users are notified through an email or through a notification that appears in the API Gateway UI. You must have the manage user administration functional privilege assigned to view the usage details in the Analytics > API usage details page.