Shared chapter
Justin Balthrop
CTO & Co-Founder, Triangle Health · Former CTO, Bird and Geni
Relationship
How we worked together
Justin and I have worked together across Geni, Yammer, MyHeritage, Bird, and now Triangle Health, where he is CTO. At Geni we built tr8n together, and years later he recruited me to Bird. Our collaboration now spans three distinct chapters of my career: social platforms and localization, global mobility infrastructure, and AI-powered healthcare.
Influence
What I learned
Justin has repeatedly pulled me toward ambitious technical problems. At Geni, we connected language systems to a global family graph. At Bird, he brought me into a company building infrastructure for the physical world. Now at Triangle Health, we are applying AI to complex healthcare workflows. Few people have influenced as many chapters of my career.
Projects
Projects we built together
Geni.com / Yammer / MyHeritage · 2007 – 2013
Geni — one shared family tree for humanity
Justin and I built tr8n together at Geni. He was also the brains behind Geni's Tree Positioning System, or TPS, creating custom graph algorithms that could perform lightning-fast searches across the global family tree. Toward the end, we explored combining TPS and tr8n so a path between any two people could become a naturally translated relationship in any language. I am not sure the experiment ever launched after we left, but it connected two of Geni's most sophisticated systems in a fascinating way.
Read the case studyGeni / Translation Exchange · 2009 – 2018
Translation Markup Language — expressing meaning, not strings
Justin and I built tr8n together at Geni, turning TML from a language model for complex Newsfeed stories into production localization infrastructure. Our work connected semantic templates, language rules, community translation, and the application runtime.
Read the case studyBird · 2018 – 2025
My story at Bird
Justin recruited me to Bird and served as CTO during its fastest years of growth. We worked together as the company expanded from a small Santa Monica startup into a global mobility platform.
Read the case studyBird · 2018 – 2025
Habitat — Bird’s geospatial operating system
Justin was CTO while Habitat evolved from a small geospatial configuration service into one of Bird's foundational global infrastructure platforms.
Read the case studyBird · 2020 Hackathon
Birdy AI — a conversational operating system before LLMs
Birdy was built during one of Bird's internal hackathons while Justin was CTO. The project reflected the culture of experimentation and internal tooling that existed across the engineering organization.
Read the case studyBird · Hackathon
Bird Flight Simulator — a virtual fleet for real platform testing
The Flight Simulator extended Bird's internal testing capabilities by creating virtual scooters that behaved like real vehicles inside the production infrastructure.
Read the case studyTriangle Health · 2025 – Present
Multi-agent AI healthcare platform
Justin and I are working together again at Triangle Health, where he is CTO. This chapter brings our long-running collaboration into AI-powered healthcare, combining conversational agents, clinical workflows, interoperability, and production platform engineering.
Read the case studyThemes
The work we shared
Elsewhere