Streamdown is a React component library that makes rendering streaming markdown content easy and beautiful. Built for AI-powered applications, it handles the unique challenges that arise when markdown is tokenized and streamed in real time.
v2.5 adds inline KaTeX support, staggered streaming animations, and a round of fixes for code blocks, CSV exports, and better Tailwind v3 compatibility.
Streaming parser improvements
The new inlineKatex option auto-completes $formula to $formula$ during streaming, avoiding ambiguity with currency symbols, and the option defaults to false. Block KaTeX completion is also fixed when streaming produces a partial closing $.
Separately, single ~ between word characters (e.g. 20~25°C) is now escaped to prevent false strikethrough rendering, controlled via a new singleTilde option that is enabled by default.
Staggered streaming animations
Streaming word and character animations now cascade sequentially rather than animating all at once. The timing is configurable via a new stagger option (default 40ms). Set stagger: 0 to restore the previous behavior.
Code blocks
Custom renderers now receive the raw metastring from the code fence via a new optional meta prop, and the lineNumbers prop lets you disable line numbers.
Long lines now scroll horizontally instead of being clipped, completed blocks no longer re-render when new streaming content arrives, and unknown or truncated language identifiers fall back to plain text highlighting instead of throwing an error.
Bug fixes
save() now prepends a UTF-8 BOM for text/csv content, so Excel on Windows correctly detects encoding. Tailwind v4-only *:last: / *:first: syntax is replaced with arbitrary variant equivalents, fixing caret rendering in Tailwind CSS v3.
Read the documentation to get started.