Apigee is a platform for developing and managing APIs. By fronting services with a proxy layer, Apigee provides an abstraction or facade for your backend service APIs and provides security, rate limiting, quotas, analytics, and more.
The following image shows the high-level architecture of Apigee:
Apigee comes in the following flavors:
A cloud version hosted by Apigee in which Apigee maintains the environment, allowing you to concentrate on building your services and defining the APIs to those services.
A hybrid version consisting of a runtime plane installed on-premises or in a cloud provider of your choice, and a management plane running in Apigee's cloud. In this model, API traffic and data are confined within your own enterprise-approved boundaries