Hayden Bleasel

Bleasel’s work has spanned product design, agency leadership and developer platforms. He founded Jellypepper, led product at Corellium and built developer tools at Vercel before joining OpenAI in March 2026. At the University of Technology Sydney, he completed degrees in business and information technology from 2012 to 2016.[1]

Generate documentation infrastructure from content

Blume takes Markdown or MDX content and supplies the documentation site around it, including navigation, search, themes and components. It manages an Astro project internally and lets users eject a standalone project when they need control. The framework also exposes machine-readable documentation formats and interfaces so agents can search and read the same material people use.[2]

Render Markdown while it is still arriving

Bleasel created Streamdown during his Vercel work. The renderer handles incomplete or unterminated Markdown produced in a streaming response, so a page can remain readable before the full answer arrives. Its implementation builds on React Markdown and includes handling for code, mathematical notation and diagrams. It can be used independently of the larger AI interface components that consume it.[1][3]

Make code-quality rules easy to apply

Ultracite packages formatting and linting conventions for development workflows. Its CLI initializes and maintains configuration around supported tools and supplies instructions for coding agents. The project aims to make shared rules available at the point code is written and checked, reducing the setup needed to apply them consistently.[4]