How Reddit’s designers build ultra-realistic prototypes with Figma + Cursor
Claire Vo talks with Blair Metcalf, principal UX engineer at Reddit, about Reddit Proto, a custom prototyping harness that lets designers and product managers build production-like prototypes with real signed-in data.
The gist
-
Blair says Reddit Proto hides Git behind a desktop app, so designers name a project and start vibe coding in Cursor using Reddit's design system.
-
Prototypes can load signed-in production data, which Blair says makes leadership take them seriously, and click-to-annotate notes get sent to Cursor as targeted edits.
-
Reddit has about 700 prototypes and 100% adoption across over 150 UX and product people, with a visual designer and animator among the best prototypers.
-
A custom MCP maps Figma frames to production tokens and components, generates a PRD, then Cursor writes draft code in a sibling repo.
-
When AI stalls, Blair gets vaguer like a movie director, giving facts and intent, echoing Claire's advice to under-prompt rather than over-prompt.
"And then down here, I said overall direction using the signed-in Reddit data and real type-aheads as user types in the search box. And then I sent that to Cursor and it vibe coded it on the spot. And this was just playing around. I was stunned. It worked."
▶ Play at 6:3958 creators recommend it, including Riley Brown, JD Ross, and Kieran Klaassen.
See all on the Cursor page"So, what you do is you copy the location in Figma. You go over to Figma MCP, you create from Figma, and it's going to make this thing that we call a feature capsule."
▶ Play at 16:3731 creators recommend it, including Ali Abdaal, Jordi Hays, and Nima Jalali.
See all on the Figma page"I don't yell at them. I know some folks do, but what I do is I take a day and then I get more vague. And we all have bots with projects and context, and I pop out of a project and I describe the thing large. Like a movie director. So, here's all the facts and then here is all ..."
▶ Play at 27:44
Claire Vo recommends it
"I like that. I do tell a lot of people just, like, under-prompt your AI. It's a lot more effective than over-prompting."
▶ Play at 28:17What they recommend · 6 picks
"And then down here, I said overall direction using the signed-in Reddit data and real type-aheads as user types in the search box. And then I sent that to Cursor and it vibe cod..."
"And then I actually took that to Gemini. Gemini could have performed better, but ChatGPT ended up making the illustration that was perfect. I took that into Cursor and generated..."
"I don't yell at them. I know some folks do, but what I do is I take a day and then I get more vague. And we all have bots with projects and context, and I pop out of a project a..."
Blair Metcalf
5 picks · guest
"And then down here, I said overall direction using the signed-in Reddit data and real type-aheads as user types in the search box. And then I sent that to Cursor and it vibe cod..."
"And then I actually took that to Gemini. Gemini could have performed better, but ChatGPT ended up making the illustration that was perfect. I took that into Cursor and generated..."
"I don't yell at them. I know some folks do, but what I do is I take a day and then I get more vague. And we all have bots with projects and context, and I pop out of a project a..."
Claire Vo
1 pick
"I like that. I do tell a lot of people just, like, under-prompt your AI. It's a lot more effective than over-prompting."
Also mentioned
Ads in this episode
Firecrawl. They're paid, so we keep them out of the picks above.
See what How I AI recommends without being paid →Related episodes
Episodes covering similar topics
More from How I AI