I will the present the first public release of ShapePipe, an open-source and modular weak-lensing measurement, analysis and validation pipeline written in Python. I will begin by giving an (easy-to-follow) introduction on how and why we measure the shapes of galaxies to map the distribution of dark matter in the Universe. I will then describe the design of the software, mentioning the numerous Python packages we used, and justify the choices we made. I will conclude by discussing some of the lessons we learned along the way and how these can be applied to other scientific software development projects.