The 6 most exciting vibe coding startups at Y Combinator’s Demo Day for its summer cohort

• Startups using AI to write code and those helping others do so are cascading inside Y Combinator.
• The incubator said a quarter of a recent batch generated 95% of its code using AI.
• Here are 6 standout vibe coding startups from the most recent Demo Day.

If you need proof that vibe coding is here to stay, look no further than Y Combinator, Silicon Valley’s famed startup accelerator.

Startups using AI to write code — and those helping others do so — are cascading inside YC’s summer cohort, according to executives and dedicated investors.

YC president and CEO Garry Tan said in March that roughly a quarter of its batch at the time generated 95% of its code using AI. And YC group partner Diana Hu said in a March YouTube video that Cursor had brought on more vibe coding inside YC beginning in summer 2024.

Vibe coding, a term coined by OpenAI founding member Andrej Karpathy, is proliferating across Silicon Valley, including in some tech job listings and certain Meta interviewing processes.

“If you’ve been watching the last few YC batches, the pattern is clear: vibe coding has gone from a fringe experiment to a mainstream startup archetype,” said Gabriel Jarrosson, managing partner at Lobster Capital, which exclusively invests in YC startups.

Another tell? YC’s venture capital partners are publishing best practices for vibe coding.

“YC rarely institutionalizes advice unless they believe a pattern is durable,” Jarrosson said.

Jared Heyman, managing partner at YC-dedicated Rebel Fund, said the number of vibe coding startups inside YC has climbed in recent years, including nine in the spring 2025 batch. He said that vibe coding and using text to code are “here to stay.”

While vibe coding has resulted in a funding frenzy, it has drawbacks. The process can be prone to errors and less useful for complex problems, engineers told Business Insider.

From tools that allow users to code on their phones to those that build AI agents using plain English, here are six standout vibe coding startups from YC’s summer 2025 batch.

Bitrig

What it does: Bitrig builds a vibe coding tool allowing users to quickly create apps by chatting with AI. It writes in Swift, the main programming language used by Apple for iOS apps.

Year founded: 2025 in Cupertino by Apple veterans Kyle Macomber, Tim Donnelly, and Jacob Xiao.

YC Partner: Brad Flora

From the founders: “At my son’s birthday party, I built an app with my niece from a single prompt: ‘Make me an app that lets me track how many hugs Amelia has given me,'” Macomber said. “When the count reaches 10, the app says ‘Wow! So many hugs!’ It was a small, fun moment that showed how magical these tools can be.”

“Once you’ve built something with code, you start to see the world differently. You notice new opportunities to save time, to improve your day, or to contribute at work.”

Floot

What it does: Floot builds a vibe coding app that helps entrepreneurs build web apps. The company says it has 14,000 users.

Year founded: 2025 in San Francisco by Yujian Yao and Edward Look.

YC Partner: Brad Flora

From the founders: “The way YC and investors look at vibe coding startups is that the market is huge, and the competition is fierce,” Yao said. “Companies that can demonstrate an edge, either through traction or by capturing a niche, are especially appealing.”

“Even we rely on Floot to build our own internal tools and major parts of Floot itself — it’s already saving us a lot of time.”

Okibi

What it does: Okibi builds a web app that lets users describe what they need in plain English to create AI agents that can talk to a company’s internal software and automate tasks.

Year founded: 2025 in San Francisco by Mahyad Ghassemibouyaghchi and Saurav Mitra, who previously cofounded the Y Combinator startup SigmaOS in 2021.

YC Partner: Gustaf Alströmer

From the founders: “I believe vibe coding is here to stay because it’s not just a temporary productivity boost. It represents a fundamental shift in how we build software,” Ghassemibouyaghchi said. “By collapsing the distance between idea and execution, vibe coding enables teams to fail faster, learn quicker, and iterate toward product-market fit much faster.”

Stagewise

What it does: Stagewise allows backend developers, designers, and product managers to build and refine web apps directly inside their browsers using visual guides. The company aims to replace frontend developers.

Year founded: 2024 by Glenn Töws and Julian Goetze, and based in Bielefeld, Germany.

YC Partner: Eric Levine

From the founders: “There is tons of untapped potential that AI-native startups are getting into step by step,” Töws told Business Insider.

“Vibe coding resonates with investors, because of its high potential of increasing throughput while — to a certain extent — reducing workforce costs.”

Vibe Code Go

What it does: Vibe Code Go builds a mobile app for software engineers that allows them to vibe code on their phones.

Year founded: 2025 by Chris Nolet and Ryan Burgoyne.

YC Partner: Tyler Bosmeny

From the founders: “Junior and midlevel engineers only get a moderate boost from agentic coding tools. They’re more productive,” Nolet said. “But it’s actually the senior and staff-level engineers who are orders of magnitude more productive. Isn’t that interesting? It’s the really senior engineers, who are already great, that are getting these truly incredible productivity gains, because they know how to prompt LLMs in just the right way.”

“I’m sure that within 10 years, ‘vibe coding’ or agentic coding will just be ‘coding.’ The vibe part will be implicit. It’s going to be subsumed into the art of software engineering.”

VibeFlow

What it does: VibeFlow builds a tool that helps non-coders generate full websites using prompts, including giving them access to backend logic.

Year founded: 2025 in San Francisco by Alessia Paccagnella and Elia Saquand.

YC Partner: Tyler Bosmeny

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