Developing ArcGIS Server applications is about remotely programming ArcObjects. The server application programming interface (API) includes a large number of ArcObjects components organized into a series of object libraries. You can build any kind of application using the server API, so it is possible to build high-performance, scalable applications, as well as extremely slow applications that do not scale.
The performance of the application is the responsibility of the developer and the GIS server administrator. They must work together to design applications that perform and scale given available hardware resources. There are a variety of techniques you can use when developing your application to optimize performance. These are described in the following topics: