To start using GraphChecker, it will first need to be installed onto your Moodle server. Because GraphChecker uses a sandbox to grade submissions, the installation procedure is slightly more involved than most other Moodle plugins. Step-by-step installation instructions are available here.
If you are using GraphChecker, or you have any questions, we would be happy to hear about it!
GraphChecker is free software licensed under GPL v3 or later – the same license as Moodle itself.
GraphChecker is based in part on CodeRunner by Richard Lobb et al. which is also under GPL v3 or later. CodeRunner is a plugin that automatically grades code written by students, and GraphChecker uses CodeRunner's infrastructure for automatic grading. See https://coderunner.org.nz for more information.