A Web services-oriented service provider middleware architecture and implementation is provided that integrates the performance monitoring of individual CPs, along with other dynamic contextual conditions, in the automatic selection of appropriate CPs. In the architecture, a CP's performance is evaluated not only in terms of network or service-level parameters, but also via other business processes (e.g., complaint handling). The selection of multiple Web services occurs through an initial filtering of a set of feasible workflows for each task depending on business agreements and end user needs, and a subsequent dynamic context-based selection of the most appropriate workflow. A workflow filtering and ranking engine uses metarules to guide the optimisation process and help in selecting and ranking the feasible workflows. The component services in the workflows are evaluated by evaluator processes of information sources. The workflow engine outputs the workflows in their preference ranking. At runtime, if the workflow and/or its components meet all the runtime requirements (performance, for example), then the workflow is selected and executed.