streamdown

SKILL.md

Streamdown

Streaming-optimized React Markdown renderer. Drop-in replacement for react-markdown with built-in streaming support, security, and interactive controls.

Quick Setup

1. Install

npm install streamdown

Optional plugins (install only what's needed):

npm install @streamdown/code @streamdown/mermaid @streamdown/math @streamdown/cjk

2. Configure Tailwind CSS (Required)
This is the most commonly missed step. Streamdown uses Tailwind for styling and the dist files must be scanned.

Tailwind v4 — add to globals.css:

@source "../node_modules/streamdown/dist/*.js";

Add plugin @source lines only for packages you have installed (omitting uninstalled plugins avoids Tailwind errors). See plugin pages for exact paths:

Code: @source "../node_modules/@streamdown/code/dist/*.js";

CJK: @source "../node_modules/@streamdown/cjk/dist/*.js";

Math: @source "../node_modules/@streamdown/math/dist/*.js";

Mermaid: @source "../node_modules/@streamdown/mermaid/dist/*.js";

Tailwind v3 — add to tailwind.config.js:

module.exports = {
  content: [
    "./app/**/*.{js,ts,jsx,tsx,mdx}",
    "./node_modules/streamdown/dist/*.js",
  ],
};

3. Basic Usage

import { Streamdown } from 'streamdown';

<Streamdown>{markdown}</Streamdown>

4. With AI Streaming (Vercel AI SDK)

'use client';
import { useChat } from '@ai-sdk/react';
import { Streamdown } from 'streamdown';
import { code } from '@streamdown/code';

export default function Chat() {
  const { messages, input, handleInputChange, handleSubmit, isLoading } = useChat();

  return (
    <>
      {messages.map((msg, i) => (
        <Streamdown
          key={msg.id}
          plugins={{ code }}
          caret="block"
          isAnimating={isLoading && i === messages.length - 1 && msg.role === 'assistant'}
        >
          {msg.content}
        </Streamdown>
      ))}
      <form onSubmit={handleSubmit}>
        <input value={input} onChange={handleInputChange} disabled={isLoading} />
      </form>
    </>
  );
}

5. Static Mode (Blogs, Docs)

<Streamdown mode="static" plugins={{ code }}>
  {content}
</Streamdown>

Key Props

Prop
Type
Default
Purpose

children
string
—
Markdown content

mode
"streaming" | "static"
"streaming"
Rendering mode

plugins
{ code?, mermaid?, math?, cjk? }
—
Feature plugins

isAnimating
boolean
false
Streaming indicator

caret
"block" | "circle"
—
Cursor style

components
Components
—
Custom element overrides

controls
boolean | object
true
Interactive buttons

linkSafety
LinkSafetyConfig
{ enabled: true }
Link confirmation modal

shikiTheme
[light, dark]
['github-light', 'github-dark']
Code themes

className
string
—
Container class

allowedElements
string[]
all
Tag names to allow

disallowedElements
string[]
[]
Tag names to disallow

allowElement
AllowElement
—
Custom element filter

unwrapDisallowed
boolean
false
Keep children of disallowed elements

skipHtml
boolean
false
Ignore raw HTML

urlTransform
UrlTransform
defaultUrlTransform
Transform/sanitize URLs

For full API reference, see references/api.md.

Plugin Quick Reference

Plugin
Package
Purpose

Code
@streamdown/code
Syntax highlighting (Shiki, 200+ languages)

Mermaid
@streamdown/mermaid
Diagrams (flowcharts, sequence, etc.)

Math
@streamdown/math
LaTeX via KaTeX (requires CSS import)

CJK
@streamdown/cjk
Chinese/Japanese/Korean text support

Math requires CSS:

import 'katex/dist/katex.min.css';

For plugin configuration details, see references/plugins.md.

References

Use these for deeper implementation details:

references/api.md — Complete props, types, and interfaces

references/plugins.md — Plugin setup, configuration, and customization

references/styling.md — CSS variables, data attributes, custom components, theme examples

references/security.md — Hardening, link safety, custom HTML tags, production config

references/features.md — Carets, remend, static mode, controls, GFM, memoization, troubleshooting

Example Configurations

Copy and adapt from assets/examples/:

basic-streaming.tsx — Minimal AI chat with Vercel AI SDK

with-caret.tsx — Streaming with block caret cursor

full-featured.tsx — All plugins, carets, link safety, controls

static-mode.tsx — Blog/docs rendering

custom-security.tsx — Strict security for AI content

Common Gotchas

Tailwind styles missing — Add @source directive or content entry for node_modules/streamdown/dist/*.js

Math not rendering — Import katex/dist/katex.min.css

Caret not showing — Both caret prop AND isAnimating={true} are required

Copy buttons during streaming — Disabled automatically when isAnimating={true}

Link safety modal appearing — Enabled by default; disable with linkSafety={{ enabled: false }}

Shiki warning in Next.js — Install shiki explicitly, add to transpilePackages

allowedTags not working — Only works with default rehype plugins

Math uses $$ not $ — Single dollar is disabled by default to avoid currency conflicts