How we built OWL, the new architecture behind our ChatGPT-based browser, Atlas

By Ken Rockot, Member of the Technical Staff and Ben Goodger, Head of Engineering, ChatGPT Atlas

Last week, we launched ChatGPT Atlas⁠, a new way to browse the web with ChatGPT by your side. In addition to being a full-featured web browser, Atlas offers a glimpse into the future: a world where you can bring ChatGPT with you across the internet to ask questions, make suggestions, and complete tasks for you. In this post, we unpack one of the most complex engineering aspects of the product: how we turned ChatGPT into a browser that gets more useful as you go.

Making ChatGPT a true co-pilot for the web meant reimagining the entire architecture of a browser: separating Atlas from the Chromium runtime. This entailed developing a new way of integrating Chromium that allows us to deliver on our product goals: instant startup, responsiveness even as you open more tabs, and creating a strong foundation for agentic use cases.

Shaping the foundation

Chromium was a natural building block. It provides a state-of-the-art web engine with a robust security model, established performance credentials, and peerless web compatibility. Furthermore, it’s developed by a global community that continuously improves it. It’s a common go-to for modern desktop web browsers.

Rethinking the browser experience

Our talented design team had ambitious goals for our user experience, including rich animations and visual effects for features like Agent mode. This required our engineering team to leverage the most modern native frameworks for our UI (SwiftUI, AppKit and Metal), instead of simply reskinning the open source Chromium UX. As a result, Atlas’ UI is a comprehensive rebuild of the entire application UX.

Our Solution: OWL

Our answer to these challenges was to build a new architectural layer we call OWL: OpenAI’s Web Layer. OWL is our integration of Chromium, which entails running Chromium’s browser process outside of the main Atlas app process.