Sherwood Callaway is the founder and chief executive of Sazabi, an AI-native observability company developing software that investigates production failures, identifies their causes, and helps engineers resolve them. A two-time Y Combinator founder, he previously co-founded healthcare automation company Opkit and led engineering for Alice, 11x’s AI sales representative.
Callaway attended Dev Bootcamp in 2014, where Ruby on Rails introduced him to thoughtfully designed developer tooling. He joined Crunchbase in 2017, working on integration testing, continuous deployment, and infrastructure, then moved to Brex in 2019 and helped establish its infrastructure, observability, and Bill Pay engineering teams.
In 2021, he and fellow Brex alumnus Justin Ko founded Opkit, which joined Y Combinator’s Summer 2021 batch. Initially focused on medical billing, the company evolved into healthcare voice automation for insurance verification, patient intake, and appointment scheduling. Its human-in-the-loop voice automation routed calls to AI agents or human operators according to task suitability, with unsuccessful automated attempts redirected for human follow-up. Callaway described the architecture as separating the customer’s desired outcome from the individual attempts required to complete it.
11x acquired Opkit in September 2024. Callaway subsequently led engineering on Alice, its autonomous sales-development product, helping replace manually entered sales information with a customer-specific knowledge base. Working alongside Satwik Singh, he developed systems that ingest company documents, websites, and recorded materials; preserve their structure through Markdown conversion and semantic chunking; and retrieve relevant context when generating outreach. Their AI Engineer World’s Fair session also detailed Pinecone-backed retrieval and an interactive visualization that lets customers inspect the knowledge available to Alice.
Practical convictions
- Automation should guarantee outcomes, not autonomy. Opkit’s human fallback protected completion rates while giving operators opportunities to learn from cases the AI could not handle.
- Agents need inspectable organizational knowledge. Effective sales outreach depends on accurate, seller-specific context, while visible source materials and retrieved passages help customers evaluate whether an agent understands their business.
- Production debugging should accumulate institutional memory. Sazabi combines codebase awareness, incident history, automated investigation, and conversational production debugging through interfaces including Slack, command-line tools, and coding agents.
- Log-first observability can simplify instrumentation. Sazabi uses application logs as its primary operational signal, aiming to investigate failures without requiring customers to assemble a separate collection of metrics, traces, dashboards, and manual alerts.
Callaway returned to founding after confronting outdated debugging workflows while building Alice. Sazabi joined Y Combinator’s Spring 2026 batch, with Ko joining the company as a founding engineer.
