Design & launch of Coteach
Summary
Coteach is an AI assistant that helps Illustrative Math teachers create and adapt lesson materials. I joined as the founding product designer when it was a Chrome extension with strong interest, but low usage. As the sole designer on a four-person team, I designed every feature 0-to-1, from research through high-fidelity and into QA. I owned design through two product direction changes: first refocusing the product on output quality, then pivoting the experience towards flexibility. We launched in March 2025 with ~2,100 sign ups in the first 30 days, and an NPS of 78.9 in the first 6 months.
Chrome extension v2, August 2024
This is the Chrome extension’s second iteration that I worked on. It focused on export quality by generating lesson materials into Google Docs (teachers’ tool of choice), and provided a rigid set of lesson adaptations based on real teacher workflows. During user interviews, I discovered that this pattern wasn’t flexible enough to capture the varied context and constraints that teachers work in.
Soft release, November 2024
We soft released with a flexible chatbot interface in teacher-centric Facebook groups to start learning from organic usage. This interface was built on open-source component defaults so we could learn fast (the polish would come later). I refined design patterns as usage came in, and engineering refined the output content quality.
Public launch, March 2025
We publicly launched with a branded interface shaped by what the soft release taught us. Updated design patterns included versioned lesson materials, suggested follow-ups, a side-by-side view of the chat and artifacts, and more.
Design system
While I was branding the product, I updated neutrals, primary colors, and fonts across the open-source library. Components, like the sheet and sidebar, were adapted for specific use cases while their core functionality remained untouched to keep implementation straight-forward.