Guinea Pig
Built at The Persistent Context Sprint Hackathon | Live at MongoDB .Local Build Fest · Aug 13, 2026 · San Francisco, CA

Guinea Pig turns dead clickstreams into a persistent population of grounded “ghosts” in MongoDB—so the product doesn’t wake up cold. PMs interview churned shoppers (cited to real events), accumulate friction patterns across restarts, and then spin a sandbox of a proposed UI change and drive hundreds of those same ghosts through it with computer control—mouse, clicks, forms—conditioned on each user’s memory, to see who would stay and who would still churn before any living customer tries it.