One of my Phd-students developed a local LTI consumer, which is now available for free on github. So if you would like to do amazing external stuff and afterwards embed it into moodle, it might be helpful:
Typically you will develop your LTI provider locally and because of that you also want to test it locally. Unfortunately no simple LTI consumer for local usage existed. So I have written one based on python, django and the python LTI library.