There is, however, a possible catch. As a developer, there's a sharp limit to what can be done purely in server-side software to mitigate a DDoS attack. Some classes of attack rely on particular kinds of server-side vulnerabilities, and against these your skills are very valuable! I'm sure your contributions of skill would be most welcome.
But against pure bandwidth-flooding attacks, it's more likely that writing more code is of at best marginal benefit. The state of the art for responding to these requires a big network, a lot of bandwith, and active management. Things difficult to deliver as a lone developer who cares deeply.