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Prototype Driven Development: Keep Your Plan Flexible as You Build with AI
Presentation

Prototype Driven Development: Keep Your Plan Flexible as You Build with AI

June 26, 2026
Presented by Marcelo Lewin
I Build with AI Meetup • In-Person

Most of us were taught to plan everything up front, then build exactly what the plan says. When you’re building products with AI, that’s backwards.

In this presentation, I’ll introduce Prototype Driven Development (PDD), a way of building where you keep your plan but hold it loosely, spinning off fast, throwaway prototypes to answer the decisions you can’t make on paper, then folding what you learn back into the plan. We’ll cover why rigid plans fail the modern builder, the idea of a prototype as a probe (not the product), the core loop and its principles, and how I use it to build my own apps. You’ll leave with a repeatable method for moving fast without flying blind.

In the hands-on workshop, we’ll build a small app together from scratch using Cody Product Builder, with Prototype Driven Development as the backbone. You’ll watch (and do) the whole loop in action: start with a plan, hit a real decision, spin off a quick prototype to settle it, capture the verdict, and feed it straight back into the build. By the end you’ll have practiced the exact workflow on a real app and have a method you can take home to your own projects. Bring your laptop, an AI agent, and an idea you’ve been wanting to build.

Marcelo Lewin

Marcelo Lewin, Founder @ iBuildWith.ai

Marcelo is the founder of iBuildWith.ai and a Principal Content Architect and Builder at Cigna. He has over 30 years of experience in the tech industry. Having lived through the computer, internet, and mobile revolutions, he is now excited and focused on navigating the AI revolution by helping non-developers build real applications using AI. He founded several startups and held roles at various companies including Toyota, NBC, J.F. Shea, and Walt Disney Imagineering.