Many workflow engines, including Argo Workflows, Tekton Pipelines, and Apache Airflow, enable users to orchestrate complex jobs. However, each of these workflow engines uses different programming paradigms and abstractions to construct workflows. Coleur hopes to enable users to construct and manage workflows on different engines through a unified interface, which offers implicity, extensibility, reusability, and efficiency. Couler also features an imperative programming style for the automatic construction of DAGs.