SageMath is an open-source project and has a very welcoming developer community. We invite newcomers to help improve the code or contribute in other ways.
Our mission is:
Creating a viable free open source alternative to
Magma, Maple, Mathematica and Matlab.
SageMath can give students and other contributors a wonderful experience in developing in a large-scale, supportive, and rigorous environment.
All code is peer-reviewed, all functions must be documented and unit-tested on a variety of platforms and systems. Python is used as a base language, Git is used as the source code revision system, and Trac is used to track all support/development issues. All of these tools are very capable and used in many other small and large-scale projects. From a software engineering standpoint, SageMath is a wonderful project to be engaged in.
The mailing lists are extremely supportive and responsive. There are several hundred people that have contributed code directly to SageMath over the years, including many leaders in mathematics, as well as software professionals, graduate students, and undergraduate students.
Contributions of all sorts are heartily welcomed, but attention is paid to making sure that the system does not become bloated and disorganized. The mission statement allows for a very wide variety of contributions.
See FAQ: Contributing to Sage for more information.