The explosive growth of the Web requires servers to be extensible and configurable. This paper describes our adaptive web server, OpenWebServer that employs a metaarchitecture. It supports dynamic adaptation of feasible design decisions in the web server design space by specifying and coordinating metaobjects that represent various aspects within the web server. We present some examples of system adaptation that change and tune configuration of concurrency, caching, logging, load balancing and fault tolerance. OpenWebServer can evolve continually beyond static and monolithic servers.