Overview
Carta (carta-md) is a lightweight Svelte markdown editor AND viewer powered by unified/remark/rehype. @humanspeak/svelte-markdown is a focused rendering component.
Type: Markdown Editor + Viewer
Approach: Split-pane editor with live preview
Feature Comparison
| Feature | @humanspeak/svelte-markdown | Carta |
|---|---|---|
| Svelte 5 Native | ||
| TypeScript Support | ||
| Markdown Rendering | ||
| Markdown Editing | ||
| Custom Renderers | Svelte components | Via plugins |
| Token Caching | ||
| HTML Tag Control | 84 tags with allow/deny | Via rehype-sanitize |
| LLM Streaming Mode Carta offers live preview for editing, but its docs do not describe a dedicated markdown streaming renderer mode. | writeChunk() / resetStream() | |
| Syntax Highlighting | Via marked extensions | Built-in plugin |
| Math (KaTeX) | Built-in extension (markedKatex) | Built-in plugin |
| Diagrams (Mermaid) | Built-in extension (markedMermaid) | Built-in plugin |
| Split-Pane UI | ||
| Keyboard Shortcuts |
Svelte Markdown Strengths
- Svelte 5 runes-native — built for runes, not retrofitted
- TypeScript-first with full type safety
- Built-in token caching (50-200x faster re-renders on repeated content)
- LLM streaming with imperative writeChunk() / resetStream() API
- 23 markdown renderers + 84 HTML tag renderers — every override is a Svelte snippet
- First-class extensions: KaTeX math, Mermaid diagrams, GitHub alerts, footnotes
- Built-in XSS protection — protocol allowlist, event-handler stripping, attribute sanitization
- Allow/deny utilities (allowHtmlOnly, excludeRenderersOnly, etc.) for fine-grained control
- Drop-in component — works anywhere in your Svelte app
- Simpler API — one component, one prop
- More granular HTML control (84 individual tag renderers)
- Snippet overrides for inline customization
Carta Strengths
- Full markdown editing experience with live preview
- Svelte-native (not a wrapper around another framework)
- Lightweight compared to ProseMirror-based editors
- Plugin system for syntax highlighting, math, etc.
- Keyboard shortcuts and toolbar
Svelte Markdown Limitations
- Smaller community (newer project)
- Runtime-only (no build-time optimization)
- No editing capabilities
- No split-pane UI
- No built-in code syntax highlighting (use a marked extension)
Carta Limitations
- Bundled editor code even if you only need rendering
- Smaller community than established editors
- No token caching
- Fewer HTML tag renderers
The Verdict
Choose Carta when you need a Svelte-native markdown editor with live preview — it is the lightest editor option in the ecosystem. Choose @humanspeak/svelte-markdown when you only need rendering — simpler, lighter, with better caching and HTML control.
Try @humanspeak/svelte-markdown
Install in seconds and render your first markdown.