YETI is a proof-of-concept implementation of the Trusted Automated eXchange of Indicator Information (TAXII) protocol. The tool supports three core TAXII services: Inbox, Poll, and Discovery services as defined by the TAXII Services Specification. Built using Python 2.7 and the Django 1.7 web application framework, YETI provides developers with a reference implementation for building and testing TAXII-compliant applications. The tool enables automated exchange of cyber threat intelligence indicators between organizations and security systems. YETI serves as both a learning resource for understanding TAXII protocol mechanics and a development foundation for creating custom threat intelligence sharing platforms. The implementation focuses on helping developers understand the technical requirements and data structures involved in TAXII-based threat intelligence exchange.