Fractional CTO: AI startup MVP to production in 14 weeks
Led architecture, hiring, and delivery for an AI workflow product — from zero to paying customers with eval harness, guardrails, and SOC2-ready foundations.
Technology Stack
Key Outcomes
- •Shipped production MVP in 14 weeks with 3 design-partner customers live
- •Built evaluation harness covering accuracy, latency, and cost per workflow run
- •Established ADR-driven architecture and 90-day roadmap tied to ARR milestones
Context
A Series A AI SaaS startup had strong founder-market fit but no production platform. Investors wanted revenue signal; engineering was two senior ICs and a contractor. They needed a Fractional CTO to ship fast without accumulating debt.
Problem
- No shared architecture; prompts lived in notebooks.
- No eval harness — every release was a gamble.
- Enterprise buyers asked about security posture before pilots.
My role
Fractional CTO (3 days/week): architecture, hiring bar, sprint rituals, and direct hands-on for the agent orchestration layer.
Approach
- Week 1–2 — KPI model (activation, cost/run, latency p95); ADR for agent vs. workflow split.
- Week 3–6 — Core API, auth, tenant isolation; first workflow templates.
- Week 7–10 — Eval harness in CI; red-team suite for prompt injection.
- Week 11–14 — Design-partner onboarding; observability and runbooks.
Architecture
React UI → FastAPI gateway → Workflow engine → LLM providers (with fallback) → PostgreSQL + vector store → LangSmith traces → CloudWatch/Grafana.
Results
Three design partners on production billing; incident rate stayed flat through launch because evals gated every release.
Lessons
Ship the harness before the hero demo. Buyers trust traces more than slide decks.
CTA
Building an AI product and need a fractional CTO? Book a 30-min call.