The frontend coding agent for real codebases.

stagewise builds an open-source frontend coding agent for real codebases. We enable backend devs, designers and product managers to build pretty and functional web apps in a simple and visually guided manner - no matter the used tech stack. stagewise lives right inside your browser, makes changes in your local codebase and is compatible with all kinds of frameworks and setups - allowing it to be retrofitted into any existing project. Our agent enables you to show and tell what you want to change - all while using your app on localhost and without having to switch to external tools. Making changes is as easy as selecting elements, giving a simple prompt like “make it green and put it in the top right corner”, and immediately seeing the result. We're two founders from Germany who met while working at a B2B SaaS startup. With Glenn's background in building dev tools for enterpries (Rheinmetall, Miele), as well as Julians experience in building web apps used by thousands (saasmetrix, strukto.io), we have the unique blend of experience and product sense needed to build this. After making our initial launch with the open-sourced toolbar that puts your favorite coding agent right inside your browser and going viral with it, we’re now launching a high-speed coding agent dedicated to frontend development - taking our product and the experience of our users to the next level. Our vision is to replace frontend devs completely, by gradually enabling both the backend devs, but also less technical designers and product managers to create well-designed applications. We start with developers who lack design experience, but our ultimate goal is to change how products are built.

Active Founders

Glenn Töws

Founder

Co-founder and CEO of stagewise, the frontend coding agent for real codebases. Studied electrical engineering at DHBW Mosbach and in partnership with Rheinmetall, focussing on functional safety in automotive embedded software. Led the efforts for development and adoption of a state-of-the-art componentization framework for embedded software at Miele, before making a pivot to artificial intelligence and web technologies.

Glenn Töws

Founder

Co-founder and CEO of stagewise, the frontend coding agent for real codebases. Studied electrical engineering at DHBW Mosbach and in partnership with Rheinmetall, focussing on functional safety in automotive embedded software. Led the efforts for development and adoption of a state-of-the-art componentization framework for embedded software at Miele, before making a pivot to artificial intelligence and web technologies.

Julian Goetze

Founder

Founder/ CTO of stagewise.io, a frontend coding agent that lives inside your browser on localhost. As a core engineer, I helped scale saasmetrix. I also built a PLG product strukto.io that helped fellow CS students from 0 to 5,000 MAU. I love building great products.

Julian Goetze

Founder

Founder/ CTO of stagewise.io, a frontend coding agent that lives inside your browser on localhost. As a core engineer, I helped scale saasmetrix. I also built a PLG product strukto.io that helped fellow CS students from 0 to 5,000 MAU. I love building great products.

Company Launches

stagewise: The frontend coding agent for production codebases

See original launch post

TL;DR

stagewise is a frontend coding agent for production codebases

→ ❌ No more tedious context switching
→ 🤝 Works with all kinds of web app frameworks
→ 🚀 Integrates into existing, production-grade apps

Get started now on stagewise.io and use the code STAGELAUNCH to get 25% off for 3 months! 🎉

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WATCH THE DEMO

https://youtu.be/q7JFZBEfyjo

ABOUT US

We’re Julian and Glenn, and we’ve built stagewise because we wanted to quickly iterate on app frontends with AI - even if they’re not just simple prototypes anymore, but real projects.

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THE PROBLEM

AI-powered app builders work great - until they don’t.

Once you move into a production-grade project setup on your local machine, you lose the awesome experience of visually building your apps frontend with simple prompts.

You move from tools like v0 or Lovable to tools like Cursor and Claude Code, but there’s a catch.

AI code editors are not good at building frontends, because:
→ They don’t understand your apps user experience
→ They don’t see your browser content, but only the codebase
→ You have to switch between browser and IDE all the time

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THE SOLUTION

With stagewise, we’ve developed an open-source and framework-independent toolbar that brings our frontend coding agent right into your web app on localhost.

Here’s how it works:
→ You prompt changes by clicking and commenting on elements in your app
→ We automatically collect browser and app metadata
→ The agent makes precise changes to your local codebase

The toolbar has already surpassed 4,800 GitHub-stars ⭐️ and 130,000 downloads 📈

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OUR VISION

We believe that the best user experiences are built by iterating fast and putting yourselves in the shoes of your user.

Our product enables teams to do exactly that - and we continue to work on a future, where awesome production-grade user experiences can be built lightning-fast and without coding skills.

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JOIN OUR COMMUNITY

👾 Join us on Discord
𝕩 Follow us on X
📬 Contact Julian or Glenn via mail

YC Photos

YC Summer 2025 Application Video