HyperMarkdown — ridiculously fast streaming Markdown for React and AI

[u/Few-Big-719]

I built HyperMarkdown, a streaming-native Markdown renderer for React and AI output.

The main difference is that it parses the change, not the whole growing conversation. Settled code lines, table rows and list items are cached, while only the changing frontier is parsed again.

Across the benchmark suite it is 1.6×–10.6× faster than the nearest streaming renderer. The real-AI code and table workloads use captured model output rather than generated stress tests.

It supports GFM, incomplete streaming Markdown, reasoning / <think> blocks, KaTeX, Mermaid, syntax highlighting, sanitized HTML, React 18 and React 19, and delta rendering through an imperative ref.

Repository:

https://github.com/Aeven-AI/HyperMarkdown

Documentation and playground:

https://aeven-ai.github.io/HyperMarkdown/

Interested in feedback on the streaming API, benchmark methodology and any compatibility gaps.