Daily API limits can bring your system to a halt unexpectedly. Your Salesforce org has a feature that can help you keep track of that API data flow: API Usage Notifications.
API Usage Notifications can be quickly set up from a Salesforce settings page. Once enabled, you can you specify an administrator to receive email notifications whenever your organization exceeds a specified limit for the number of API requests made in a specified span of hours. Then, from the API notifications detail page in Salesforce, you can edit or delete notifications and see details about them, such as who is getting notified, how often, and at what thresholds.
-Ryan and the CMB Team