New Customization Features

Streamdown v2.4 introduces powerful customization hooks for developers who need to tailor markdown rendering to their applications. The new icons prop allows teams to override built-in icons by passing a custom component map, giving developers fine-grained control over visual presentation.

The createCodePlugin now supports:

• Light and dark theme options: Configure separate Shiki themes for light and dark modes with the themes object
• Custom line numbering: Use the startLine meta option to begin line numbers at any value
• Inline code styling: The new inlineCode virtual component enables independent styling of inline code versus code blocks

Internationalization and Accessibility

This release adds native support for internationalization (i18n) and text directionality. The dir prop automatically detects and applies left-to-right or right-to-left formatting based on Unicode character analysis, with support for languages like Arabic and Hebrew. Teams can customize all UI text via the translations prop.

Enhanced Table Controls and Streaming

Tables now include fullscreen overlay capabilities controlled through the controls prop, complete with scroll locking and Escape key dismiss support. Developers can hook into streaming animations with the new onAnimationStart and onAnimationEnd callbacks for fine-tuned control over markdown rendering behavior.

Bug Fixes and Tailwind v4 Support

This release resolves issues where empty lines collapsed in syntax-highlighted code blocks and where ordered lists would retrigger animations during streaming. For projects using Tailwind CSS v4, the new prefix prop namespaces utility classes to prevent collisions with existing styles.