  In this paper, we introduce a new quantum circuit synthesis (QCS) framework,
Qsyn, for developers to research, develop, test, experiment, and then
contribute their QCS algorithms and tools to the framework. Our framework is
more developer-friendly than other modern QCS frameworks in three aspects: (1)
We design a rich command-line interface so that developers can easily design
various testing scenarios and flexibly conduct experiments on their algorithms.
(2) We offer detailed access to many data representations on different abstract
levels of quantum circuits so that developers can optimize their algorithms to
the extreme. (3) We define a rigid developing flow and environment so that
developers can ensure their development qualities with the best modern software
engineering practices. We illustrate the friendliness of our framework with a
showcase of developing a T-Count Optimization algorithm and demonstrate our
performance superiority with fair comparisons to other modern QCS frameworks.
