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Editor + Viewer vs Pure Renderer

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FIG-001

SHEET 01 / 07

FIG-002 / OVERVIEW

at a glance.

Compare Carta and @humanspeak/svelte-markdown: a Svelte markdown editor and viewer versus a focused Svelte 5 renderer with caching and HTML filtering.

FIG-003 / FEATURE MATRIX

side-by-side.

Every surface that matters, compared without spin.

feature	@humanspeak/svelte-markdown	Carta
Svelte 5 Compatibility	yes	yes
TypeScript Support	yes	yes
Markdown Rendering	yes	yes
Markdown Editing	no	yes
Custom Renderers	Svelte components	Via plugins
Token Caching	yes	no
HTML Safety Carta explicitly does not sanitize user input by default and recommends configuring DOMPurify or sanitize-html.	URL + attribute sanitization enabled by default	Consumer-supplied sanitizer
LLM Streaming Mode Carta offers live preview for editing, but its docs do not describe a dedicated markdown streaming renderer mode.	writeChunk() / resetStream()	no
Streaming HTML Output Carta is an authoring editor with live preview, not a renderer for streaming agent output with nested HTML.	Partial blocks reconcile when </tag> arrives	no
Reactive Viewer Carta documents that its standalone Markdown component is not reactive.	yes	Manual render() or keyed remount
Syntax Highlighting	Opt-in Shiki extension	Built-in plugin
Math (KaTeX)	Built-in extension (markedKatex)	Built-in plugin
Diagrams (Mermaid)	Built-in extension (markedMermaid)	Via unified/community plugin
Split-Pane UI	no	yes
Keyboard Shortcuts	no	yes

FIG-004 / STRENGTHS

where each shines.

▣ svelte markdown 13

+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
+24 markdown renderers + 83 HTML tag renderers — every override is a Svelte snippet
+First-class extensions: KaTeX math, Mermaid diagrams, GitHub alerts, footnotes
+Opt-in Shiki syntax highlighting (streaming-compatible, tree-shaken from core)
+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 (83 individual tag renderers)
+Snippet overrides for inline customization

▢ carta 5

+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, toolbar, 150+ remark plugins, and component embeds

FIG-005 / LIMITATIONS

where each falls short.

▣ svelte markdown 4

−Smaller community (newer project)
−Runtime-only (no build-time optimization)
−No editing capabilities
−No split-pane UI

▢ carta 5

−Bundled editor code even if you only need rendering
−Smaller community than established editors
−No sanitization by default
−Standalone Markdown viewer is not reactive without manual handling
−No token caching

FIG-006 / VERDICT

the honest call.

Choose Carta when you need a Svelte-native markdown editor and viewer with live preview, authoring controls, and access to remark plugins. Choose @humanspeak/svelte-markdown for reactive or streaming display, built-in caching, granular HTML rendering, and safer defaults.

FIG-007 / MORE