Blog

Engineering notes from 9io.

How we build products, AI systems and trading infrastructure — and what we learn on the way. Written by the people who do the work, with the sources linked.

Voice AI

What we learned building a voice tutor that draws while it talks

What broke in three versions of a voice tutor that draws as it talks, built on OpenAI’s Realtime API and GPT-Live, and the API details behind each problem.

29 September 2026 · 11 min read