Justin Ko is Co-Founder at Sazabi, the AI-native observability platform built for fast-moving engineering teams that replaces legacy tools like Datadog and Sentry with autonomous, AI-driven alerts and conversational debugging.

Justin studied entrepreneurship at the University of Southern California and went on to become an early engineer at Brex, working across the Growth, Card, and Cash engineering teams, before co-founding SpeakGenius, an English learning tool.

Justin brings a rare combination of deep infrastructure engineering experience and serial entrepreneurship, having successfully navigated two YC-backed ventures and an acquisition.

Justin co-founded Opkit (YC S21) alongside Sherwood Callaway in 2021, building one of the first AI phone calling services for healthcare, which was later acquired by 11x in 2024. He then co-founded Sazabi, now part of the YC P26 batch, backed by engineering leaders from Vercel, Graphite, LangChain, Replit, and more.

Sazabi is redefining observability for AI-native engineering orgs by enabling teams to instrument apps in minutes with zero code changes and resolve incidents through natural language Q&A, positioning itself as essential infrastructure for the AI-written software era.