This paper proposes an approach to the design of configurable and open middleware platforms based on the concept of reflection. More specifically, the paper introduces a language-independent reflective architecture featuring a perobject meta-space, the use of meta-models to structure meta-space, and a consistent use of object graphs for composite components. This is complemented by a component framework supporting the construction of meta-spaces. The paper also reports on experiences of implementing the architecture (with emphasis on experiments with open bindings).