Lenny's Written Position
AI prototyping collapses the traditional design-to-development handoff — PMs can now validate ideas before involving engineering.
Starting with JSON data structures (not UI mockups) leads to better AI-generated prototypes because it forces clarity of thinking about the product.
The two biggest barriers to AI prototyping adoption on product teams are making prototypes look good enough for stakeholders and figuring out team workflows instead of individual silos.
Building a reusable component library is the single biggest improvement teams can make to AI prototyping quality, allowing brand-consistent prototypes without manual cleanup each time.
AI prototyping introduces a new 'medium fidelity' tier — better than napkin drawings but not as polished as finalized Figma mocks — and choosing the right fidelity for each context is critically important.
The code generated by AI prototyping tools is mostly useless to engineering teams because it does not follow existing patterns, use the same libraries, or even use the same programming language.
The 'baselines and forks' workflow — creating a high-quality reproduction of your current product then duplicating it to explore new ideas — is the best way to rapidly test multiple design directions without rebuilding each time.
Using the Figma MCP server with Cursor allows AI agents to autonomously take screenshots, extract design tokens, and get CSS from Figma's Dev Mode, producing prototypes indistinguishable from the real product.
Prototypes should replace PRDs in fast-moving environments because PRDs block valuable design and engineering work, are almost never up-to-date, and become watered-down versions of the actual product once it exists.
The Foundation Sprint is a two-day workshop that helps teams define their Founding Hypothesis by clarifying customer, approach, and differentiation before building anything.
Google Meet succeeded only after the team stripped away complex features like 3D virtual conference rooms and focused on the core hypothesis of being the fastest and easiest video call software.
Podcast Moments
“This design process that designers have been taught, where you go off and do a bunch of research and discovery, and then you diverge, converge, diverge, converge — we sort of treated as gospel. That's basically dead.”
Jenny Wen · Jenny Wen
“There are basically two types of design work now. The first is supporting implementation and execution — engineers are using their seven Claudes to create features. The second is creating the vision or direction, but now it's a three to six month vision, not a two to five year one, and it's sometimes just creating a prototype that points people in the right direction.”
Jenny Wen · Jenny Wen
“Vibe coding is exactly good for this — Cursor and DigitalOcean and Cloudflare will get you a long way. But vibe coding also doesn't really scale.”
How to show up in any room with a low heart rate: Silicon Valley’s missing etiquette playbook | Sam Lessin · Sam Lessin
“I start every AI prototype with a JSON schema. Not a wireframe, not a design. JSON. Because it forces you to think about what the product actually does before how it looks.”
The secret to better AI prototypes: Why Tinder’s CPO starts with JSON, not design | Ravi Mehta (product advisor, previously EIR at Reforge) · Ravi Mehta
“The best PMs I know right now are all building. Not writing specs and throwing them over the wall. Actually building prototypes, testing them with users, iterating in real-time.”
The secret to better AI prototypes: Why Tinder’s CPO starts with JSON, not design | Ravi Mehta (product advisor, previously EIR at Reforge) · Ravi Mehta
“As a PM, you need to start looking more like a hybrid PM prototyper, who has some good design sensibilities.”
How we restructured Airtable’s entire org for AI | Howie Liu (co-founder and CEO) · Howie Liu
“This is a pattern with AI, you won't know what to polish until after you ship. My dream is that we ship daily.”
Inside ChatGPT: The fastest-growing product in history | Nick Turley (Head of ChatGPT at OpenAI) · Nick Turley
“When you show up with an iPhone, you're thinking about sharing. When you show up with a film camera, you're thinking about saving film. When you show up with a digital SLR, you just take a whole bunch of pictures. Be conscious about how the tools you pick are going to impact the thing that you produce.”
35 years of product design wisdom from Apple, Disney, Pinterest, and beyond | Bob Baxley · Bob Baxley
“The biggest role shift is prototyping happening earlier in the process. PMs and designers that have an idea will use Claude and maybe even Artifacts to put together an actual functional demo. That has been very, very helpful.”
Anthropic’s CPO on what comes next | Mike Krieger (co-founder of Instagram) · Mike Krieger
“If you're not prototyping and building to see what you want to build, I think you're doing it wrong. It becomes even more important to have taste-making at the heart of it because otherwise you just have a Frankenstein product.”
Microsoft CPO: If you aren’t prototyping with AI, you’re doing it wrong | Aparna Chennapragada · Aparna Chennapragada
“Now we have 600 engineers. Some of the best things created with v0 have not come from our engineering team. They've come from the marketing team, the sales team, the product management team. The product management team is fascinating, because now they're actually building the product.”
Everyone’s an engineer now: Inside v0’s mission to create a hundred million builders | Guillermo Rauch (founder and CEO of Vercel, creators of v0 and Next.js) · Guillermo Rauch
“Those sessions with Jason, they were short, very intense sessions where you're trying to crack the nut together. It wasn't sitting alone writing a document, it wasn't making a bunch of requirements. It wasn't making a beautiful Figma file. It was this super intense collaborative 'what about this? what about that?'”
A better way to plan, build, and ship products | Ryan Singer (creator of “Shape Up,” early employee at 37signals) · Ryan Singer
“As the company gets bigger, you can actually create alignment by causing internal virality. We would create prototype products, share the build, and it would explode inside the company. Day after day we would hear from engineers, then managers, then VPs, then eventually from Evan.”
How to win in the AI era: Ship a feature every week, embrace technical debt, ruthlessly cut scope, and create magic your competitors can't copy | Gaurav Misra (CEO and co-founder of Captions) · Gaurav Misra
“On any Figma URL, when you're looking at a design that you've made, if you just put bolt.new in front of that URL and hit enter, it's going to suck that design into Bolt, and turn it into a full stack app or mobile app, just out of the box.”
Inside Bolt: From near-death to ~$40m ARR in 5 months—one of the fastest-growing products in history | Eric Simons (founder and CEO of StackBlitz) · Eric Simons
“Just start simple and then what you get is that the AI says, okay, I can go through what does a beautiful Airbnb clone look like and it goes through a bit of design decisions and then I'll zoom out to see more of it. We have this just UI that is... I mean it has all the nice things you would expect from Airbnb clone where you see different categories and you can see two listings from Airbnb with login buttons and everything.”
Building Lovable: $10M ARR in 60 days with 15 people | Anton Osika (co-founder and CEO) · Anton Osika
“The best way to build an AI product is to use it yourself constantly. Our team uses Replit Agent to build Replit. That feedback loop is the fastest way to improve.”
Behind the product: Replit | Amjad Masad (co-founder and CEO) · Amjad Masad
“There's this tool called websim where you can just type in a URL that doesn't exist and it will generate the entire website for you. It's wild. I think it shows you where things are going.”
Dylan Field live at Config: Intuition, simplicity, and the future of design · Dylan Field
“We lean heavily into designing and prototyping even before a project gets a green light. If you and your team do your job correctly, what does the world look like?”
Vision, conviction, and hype: How to build 0 to 1 inside a company | Mihika Kapoor (Product at Figma) · Mihika Kapoor
“So at the feature level, you'd prototype by doing a design, a mockup, and you'd take that mockup and you'd share it with somebody and say, 'Here's a mockup of the feature that I'm trying to build. What do you think?' And they'd tell you what's right or wrong, and you'd throw out the original prototype, because it wasn't very good and you'd make a new one.”
Building better product roadmaps | Janna Bastow (Mind the Product, ProdPad) · Janna Bastow
Cutting Room Floor
Guest insights on this topic that Lenny hasn't (yet) written about in his newsletters. Potential material for future posts.
“Just start simple and then what you get is that the AI says, okay, I can go through what does a beautiful Airbnb clone look like and it goes through a bit of design decisions and then I'll zoom out to see more of it. We have this just UI that is... I mean it has all the nice things you would expect from Airbnb clone where you see different categories and you can see two listings from Airbnb with login buttons and everything.”
Building Lovable: $10M ARR in 60 days with 15 people | Anton Osika (co-founder and CEO) · Anton Osika
“So at the feature level, you'd prototype by doing a design, a mockup, and you'd take that mockup and you'd share it with somebody and say, 'Here's a mockup of the feature that I'm trying to build. What do you think?' And they'd tell you what's right or wrong, and you'd throw out the original prototype, because it wasn't very good and you'd make a new one.”
Building better product roadmaps | Janna Bastow (Mind the Product, ProdPad) · Janna Bastow