Super simple implementation of an LTI 1.1 provider in Ruby using Sinatra.
Clone the code, bundle install (in Ruby 3+) to pull the gem requirements and then run with ruby basic.rb
You'll need to point an LTI consumer at this tool to see any output.
Based on examples from https://github.com/instructure/ims-lti
LTI spec and dev info can be found at http://developers.imsglobal.org/