The developing environment presented in this paper is built around an interactive tool that can accompany the software engineer for the whole software development process of concurrent and distributed applications. This environment relies on a concept of active object that is used homogeneously from the specification of the architecture down to the implementation. It provides support for architecture design, behaviour specification, automatic code production, compilation, debugging as well as formal verification. First of all, the application architecture is built with a graphical editor, translated into an architecture description language compatible with CORBA-IDL, and used to produce code that may be automatically linked and compiled into CORBA compatible implementation. The debugging of a distributed application is supported by features such as event stepping, simulation of the CORBA mechanism within a single Unix process, code tracing, etc. The formal verification is supported by translators providing Promela code that can be analysed by the SPIN model checker.