AWS Cost Explorer API enables the users to access the Reserved Instances Coverage Information

Reserved Instance coverage keeps a track over the numbers of running instances hours that are been covered by RIs which will allow you to understand the Reserved coverage at a high level or provides detailed information by filtering for a particular set of regions, accounts, tags, instance types and more. From there you can utilize the insights collected from the data to optimize Reserved Purchases for cost efficiency. The AWS Cost Explorer API is a low latency query service that offers programmatic access to the AWS Cost Explorer dataset which consists of usage data, cost allocation tags, cost as well as advanced metrics.