###### Abstract  
The construction industry is characterized by the diversity of its processes, whereby persons involved in changing project communities are confronted with a changing interplay of software applications. Therefore, planning workflows, and especially the exchange of information between stakeholders, need to be formalized. The automation and execution of these workflows go one step further to achieve added value in implementation and project management using building information modeling. For the configuration and execution of collaborative BIM workflows with compatible software products, a framework is conceived and developed that enables the modeling of project-specific workflows by linking individual software tools based on a standardized process notation. The resulting toolchains enable seamless information exchange between applications that integrate an openCDE-compliant web interface. The methodological approach in this paper is a concept implementation, including a proof of concept. For the concept development, a review of the state of the art is conducted, and requirements are analyzed. The concept development comprises data models and API descriptions and includes the concept of a central integration platform. The interaction between workflow management on the platform and the execution of tasks in the software product clients is explained. The implementation of the toolchains on the proposed platform is evaluated in a demonstrator scenario. BIM; workflows; toolchains; information container; openCDE; integration platform; REST API; software products 2022202  
in a meaningful way in some cases, especially if several participants work collaboratively on building models [5]. An alternative to the file-based exchange is the asynchronous exchange of information via web interfaces. The development and use of web interfaces support the tendency of construction IT products moving toward the cloud. In addition, software is increasingly being offered as a scalable service-on-demand, i.e., customers do not purchase software licenses but use the functionality [5; 6; 7]. Moreover, the exchange of information via web interfaces is gaining relevance in the construction industry due to their standardization. In this regard, the international standard ISO 19650-1 [8] defines terms and principles for information management with BIM. It contains recommendations for specifying the management, exchange, recording, versioning, and organization of information for involved stakeholders [8]. In addition, the specification DIN SPEC 91391-2 [9] recommends the use of web interfaces for Common Data Environments (CDE) data exchange of different vendors. To improve the data exchange and simplify the connection of software products for developers, the specification also provides a conceptual basis. It sets out the requirements for procedures and structures when exchanging data between two CDEs or between a CDE and another software product [9]. The usage of standardized openCDE-compliant web interfaces may increase the competitiveness of small and medium-sized construction IT product providers. Furthermore, it facilitates market entry, helps to simplify the initialization of construction projects, reduces investment costs, and promotes collaborative working with BIM. The integration platform developed in the scope of the Software Reference Architecture for openBIM Services (BIMSWARM) project may serve as a central point of contact for information on IT products in the construction industry and corresponding certifications in Germany. An essential core function of the platform is the linking of applications, services and content in common workflows to build holistic digital value chains for BIM-based construction planning, execution and operation, which are subsequently termed toolchains. The user-friendly configuration of such toolchains is ensured by a web user interface called composer. Via an Application Programming Interface (API), client software products can be integrated into these toolchains and interact with the platform.