The aim of the thesis is to create a fully working mocking tool that weakens dependencies between groups involved in large-scale software development. Mainly dependencies between developers and QA engineers, but also between developers and product managers or designers during early stages of software life cycle. The thesis shall describe specifics of large-scale software development, compare existing tools that address similar issues, and finally design and implement an application based on previous findings. The outcome of the thesis is going to be a web application ready to be used in real-life environment. The tool will be open-source and easily applicable to various types of use cases. The aim of the thesis is to create a mocking tool that weakens dependencies between groups involved in large-scale software development. The thesis should describe specifics of large-scale software development, compare existing tools that solve similar issues, and finally design and implement an application based on previous findings. The core of the thesis shall provide in-depth description of the design and implementation process of the actual tool. The outcome of the thesis is a fully working web application called Paper Plane. The application will utilize OpenAPI standard and should be ready for deployment in a real-life environment. Paper Plane will be open-source and applicable to various types of use cases.