In general, live coding is where people write code using a programming language, in order to change a live process. Rather than writing code, compiling it and then running it, live coders write code while a computer reads and processes it. This leads to an immediate feedback cycle, where the programmer is able to manipulate a running system, quickly trying out ideas and seeing, hearing or otherwise experiencing the results without any break of flow. In principle, live coding techniques can be applied to just about any programming activity, and over the past ten years has supported a fast growing community of creative practitioners making live music, live video, live choreography and more. At the same time, there has been a resurgence of interest in liveness in software engineering and computer science in general, bringing new focus on human factors in programming language experience design and the psychology of programming.
For more on live coding practice, see the Transnational Organisation for the Promotion of Live Algorithm Programming (TOPLAP) website.