Monaco Editor vs CodeMirror 6 vs Sandpack: In-Browser Code Editors 2026

TL;DR

Embedding a code editor in a browser-based application — playgrounds, online IDEs, documentation, admin panels, notebook environments — comes down to three principal options in 2026. Monaco Editor is the VS Code editor engine, open-sourced by Microsoft — it brings the full VS Code experience (IntelliSense, multi-cursor, go-to-definition, full TypeScript language server) in a 2–5MB bundle that works but is heavy for most use cases. CodeMirror 6 is the complete rewrite from 2021 — modular, lightweight (tree-shakeable from ~50kB for a basic editor), highly extensible, excellent accessibility, and used by Firefox DevTools, Replit, and many others; it's the right choice for most custom editor integrations. Sandpack is CodeSandbox's live preview stack — it combines a CodeMirror-based editor with a browser-based Node.js runtime (via Nodebox) to run and preview actual React/JavaScript code without a server; it's purpose-built for interactive code examples and playgrounds. For feature-complete IDE experience with TypeScript IntelliSense: Monaco. For custom editor integration with minimal bundle overhead: CodeMirror 6. For live React/JavaScript playgrounds with code execution: Sandpack.

Key Takeaways

• Monaco is VS Code — same engine, full IntelliSense, ~5MB gzipped, needs lazy loading
• CodeMirror 6 is modular — install only what you need, ~50-200kB depending on features
• Sandpack executes code — runs actual JavaScript/TypeScript/React in the browser via Nodebox
• Monaco requires a worker — needs MonacoWebpackPlugin or equivalent for service workers
• CodeMirror 6 has better mobile support — fully keyboard accessible, touch-friendly
• Sandpack uses CodeMirror — the editor layer is CodeMirror 6, not a standalone editor
• Monaco supports all VS Code extensions syntax — TextMate grammars for 500+ languages

Use Case Map

Full IDE in browser (TypeScript playground)  → Monaco Editor
Lightweight custom code editor               → CodeMirror 6
Interactive React/JS playground              → Sandpack
Documentation code examples (editable)      → Sandpack or CodeMirror 6
SQL/YAML/JSON editor in admin panel         → CodeMirror 6
Low-bandwidth or mobile-first editor        → CodeMirror 6
Notebook (Jupyter-like) cells               → CodeMirror 6
Code review / diff display                  → Monaco (diff editor) or CodeMirror 6

Monaco Editor: The VS Code Engine

Monaco is VS Code's editor component extracted as a standalone library. If you want TypeScript IntelliSense, hover tooltips, and refactoring tools in the browser, this is the starting point.

Installation

npm install @monaco-editor/react
# Or vanilla (larger, more control):
npm install monaco-editor

React Integration

// The simplest path — @monaco-editor/react
import Editor from "@monaco-editor/react";

export function CodeEditor() {
  return (
    <Editor
      height="400px"
      defaultLanguage="typescript"
      defaultValue={`// TypeScript with full IntelliSense
interface User {
  id: number;
  name: string;
  email: string;
}

function greet(user: User): string {
  return \`Hello, \${user.name}!\`;
}`}
      theme="vs-dark"
      options={{
        minimap: { enabled: false },
        fontSize: 14,
        tabSize: 2,
        wordWrap: "on",
        scrollBeyondLastLine: false,
        automaticLayout: true, // Resize on container resize
      }}
    />
  );
}

Controlled Editor with Change Handlers

import Editor from "@monaco-editor/react";
import { useState, useRef } from "react";
import type { Monaco } from "@monaco-editor/react";
import type { editor } from "monaco-editor";

interface CodeEditorProps {
  initialValue: string;
  language: string;
  onChange?: (value: string) => void;
  readOnly?: boolean;
}

export function CodeEditor({ initialValue, language, onChange, readOnly = false }: CodeEditorProps) {
  const [value, setValue] = useState(initialValue);
  const editorRef = useRef<editor.IStandaloneCodeEditor | null>(null);

  function handleEditorDidMount(editor: editor.IStandaloneCodeEditor, monaco: Monaco) {
    editorRef.current = editor;

    // Add keyboard shortcut
    editor.addCommand(monaco.KeyMod.CtrlCmd | monaco.KeyCode.KeyS, () => {
      console.log("Save:", editor.getValue());
    });

    // Focus editor
    editor.focus();
  }

  function handleChange(newValue: string | undefined) {
    const v = newValue ?? "";
    setValue(v);
    onChange?.(v);
  }

  return (
    <Editor
      height="400px"
      language={language}
      value={value}
      onChange={handleChange}
      onMount={handleEditorDidMount}
      theme="vs-dark"
      options={{
        readOnly,
        minimap: { enabled: false },
        fontSize: 14,
        lineNumbers: "on",
        folding: true,
        renderWhitespace: "selection",
      }}
    />
  );
}

TypeScript IntelliSense Configuration

import Editor, { useMonaco } from "@monaco-editor/react";
import { useEffect } from "react";

export function TypeScriptEditor() {
  const monaco = useMonaco();

  useEffect(() => {
    if (!monaco) return;

    // Configure TypeScript compiler options
    monaco.languages.typescript.typescriptDefaults.setCompilerOptions({
      target: monaco.languages.typescript.ScriptTarget.ES2020,
      allowNonTsExtensions: true,
      moduleResolution: monaco.languages.typescript.ModuleResolutionKind.NodeJs,
      module: monaco.languages.typescript.ModuleKind.CommonJS,
      noEmit: true,
      esModuleInterop: true,
      jsx: monaco.languages.typescript.JsxEmit.React,
      reactNamespace: "React",
      allowJs: true,
      typeRoots: ["node_modules/@types"],
    });

    // Add custom type definitions
    const libSource = `
      declare module "my-lib" {
        export function doSomething(input: string): number;
        export interface Config {
          debug: boolean;
          timeout: number;
        }
      }
    `;
    monaco.languages.typescript.typescriptDefaults.addExtraLib(
      libSource,
      "file:///node_modules/my-lib/index.d.ts"
    );

    // Configure diagnostics
    monaco.languages.typescript.typescriptDefaults.setDiagnosticsOptions({
      noSemanticValidation: false,
      noSyntaxValidation: false,
    });
  }, [monaco]);

  return (
    <Editor
      height="400px"
      defaultLanguage="typescript"
      defaultValue={`import { doSomething } from "my-lib";
const result = doSomething("hello"); // IntelliSense works!
`}
      theme="vs-dark"
    />
  );
}

Diff Editor

import { DiffEditor } from "@monaco-editor/react";

export function CodeDiff({ original, modified }: { original: string; modified: string }) {
  return (
    <DiffEditor
      height="400px"
      language="typescript"
      original={original}
      modified={modified}
      theme="vs-dark"
      options={{
        renderSideBySide: true,
        readOnly: true,
        minimap: { enabled: false },
      }}
    />
  );
}

Lazy Loading (Required for Performance)

// next.config.js — exclude monaco from SSR
const nextConfig = {
  webpack: (config) => {
    // Monaco needs workers — use MonacoWebpackPlugin
    return config;
  },
};

// Component — dynamic import to avoid SSR
import dynamic from "next/dynamic";

const Editor = dynamic(
  () => import("@monaco-editor/react"),
  {
    ssr: false,
    loading: () => <div>Loading editor...</div>,
  }
);

CodeMirror 6: Modular and Lightweight

CodeMirror 6 (released 2021) is a complete rewrite with a modular architecture — each feature is a separate package. You compose the editor from extension packages.

Installation

# Core packages
npm install @codemirror/view @codemirror/state

# Language support (pick what you need)
npm install @codemirror/lang-javascript @codemirror/lang-css @codemirror/lang-html
npm install @codemirror/lang-json @codemirror/lang-sql @codemirror/lang-python
npm install @codemirror/lang-markdown

# Themes
npm install @codemirror/theme-one-dark

# Common extensions
npm install @codemirror/commands @codemirror/search @codemirror/fold

# Or use the convenience package (includes everything)
npm install codemirror

Basic Setup (Vanilla JS)

import { EditorView, basicSetup } from "codemirror";
import { javascript } from "@codemirror/lang-javascript";
import { oneDark } from "@codemirror/theme-one-dark";

const view = new EditorView({
  doc: `function hello(name: string) {
  return \`Hello, \${name}!\`;
}`,
  extensions: [
    basicSetup,           // Line numbers, search, history, etc.
    javascript({ typescript: true }),
    oneDark,
    EditorView.lineWrapping,
    EditorView.updateListener.of((update) => {
      if (update.docChanged) {
        console.log("Changed:", update.state.doc.toString());
      }
    }),
  ],
  parent: document.getElementById("editor")!,
});

React Integration (useCodeMirror)

import { useEffect, useRef } from "react";
import { EditorView, basicSetup } from "codemirror";
import { EditorState } from "@codemirror/state";
import { javascript } from "@codemirror/lang-javascript";
import { oneDark } from "@codemirror/theme-one-dark";
import { keymap } from "@codemirror/view";
import { defaultKeymap, indentWithTab } from "@codemirror/commands";

interface CodeMirrorEditorProps {
  initialValue: string;
  language?: "javascript" | "typescript";
  onChange?: (value: string) => void;
  readOnly?: boolean;
}

export function CodeMirrorEditor({
  initialValue,
  language = "typescript",
  onChange,
  readOnly = false,
}: CodeMirrorEditorProps) {
  const containerRef = useRef<HTMLDivElement>(null);
  const viewRef = useRef<EditorView | null>(null);

  useEffect(() => {
    if (!containerRef.current) return;

    const view = new EditorView({
      state: EditorState.create({
        doc: initialValue,
        extensions: [
          basicSetup,
          keymap.of([...defaultKeymap, indentWithTab]),
          javascript({ typescript: language === "typescript", jsx: true }),
          oneDark,
          EditorState.readOnly.of(readOnly),
          EditorView.updateListener.of((update) => {
            if (update.docChanged) {
              onChange?.(update.state.doc.toString());
            }
          }),
        ],
      }),
      parent: containerRef.current,
    });

    viewRef.current = view;

    return () => {
      view.destroy();
    };
  }, []); // Only on mount — value changes handled imperatively

  // Update content programmatically (when value changes externally)
  useEffect(() => {
    const view = viewRef.current;
    if (!view) return;

    const current = view.state.doc.toString();
    if (current !== initialValue) {
      view.dispatch({
        changes: {
          from: 0,
          to: view.state.doc.length,
          insert: initialValue,
        },
      });
    }
  }, [initialValue]);

  return <div ref={containerRef} style={{ height: "400px", overflow: "auto" }} />;
}

Custom Extension: Autocomplete

import { autocompletion, CompletionContext, CompletionResult } from "@codemirror/autocomplete";

// Custom completion source
function myCompletions(context: CompletionContext): CompletionResult | null {
  const word = context.matchBefore(/\w*/);
  if (!word || (word.from === word.to && !context.explicit)) return null;

  return {
    from: word.from,
    options: [
      { label: "useEffect", type: "function", info: "React hook for side effects" },
      { label: "useState", type: "function", info: "React hook for state" },
      { label: "useCallback", type: "function", info: "Memoize callback functions" },
      { label: "useMemo", type: "function", info: "Memoize expensive computations" },
    ],
  };
}

// Add to extensions
const extensions = [
  basicSetup,
  javascript({ typescript: true }),
  autocompletion({ override: [myCompletions] }),
];

Custom Theme

import { EditorView } from "@codemirror/view";
import { HighlightStyle, syntaxHighlighting } from "@codemirror/language";
import { tags as t } from "@lezer/highlight";

const myTheme = EditorView.theme({
  "&": {
    color: "#c9d1d9",
    backgroundColor: "#0d1117",
    fontSize: "14px",
    fontFamily: "'Fira Code', monospace",
    borderRadius: "8px",
    padding: "8px",
  },
  ".cm-content": {
    caretColor: "#58a6ff",
    padding: "8px 0",
  },
  ".cm-line": {
    padding: "0 8px",
  },
  ".cm-activeLine": {
    backgroundColor: "#161b22",
  },
  ".cm-gutters": {
    backgroundColor: "#0d1117",
    color: "#484f58",
    border: "none",
  },
});

const myHighlightStyle = HighlightStyle.define([
  { tag: t.keyword, color: "#ff7b72" },
  { tag: t.string, color: "#a5d6ff" },
  { tag: t.comment, color: "#8b949e", fontStyle: "italic" },
  { tag: t.function(t.variableName), color: "#d2a8ff" },
  { tag: t.number, color: "#79c0ff" },
]);

const extensions = [
  myTheme,
  syntaxHighlighting(myHighlightStyle),
];

Or use @uiw/react-codemirror (Popular React Wrapper)

// npm install @uiw/react-codemirror @codemirror/lang-javascript
import CodeMirror from "@uiw/react-codemirror";
import { javascript } from "@codemirror/lang-javascript";
import { oneDark } from "@codemirror/theme-one-dark";

export function SimpleEditor() {
  return (
    <CodeMirror
      value={`const greeting = "Hello, World!";`}
      height="300px"
      extensions={[javascript({ jsx: true })]}
      theme={oneDark}
      onChange={(value) => console.log(value)}
    />
  );
}

Sandpack: Live Execution Playgrounds

Sandpack from CodeSandbox embeds a full browser-based runtime — it can actually run and hot-reload React/JavaScript code in the browser without any server.

Installation

npm install @codesandbox/sandpack-react

Basic Playground

import { Sandpack } from "@codesandbox/sandpack-react";

export function ReactPlayground() {
  return (
    <Sandpack
      template="react-ts"
      theme="dark"
      options={{
        showNavigator: false,
        showTabs: true,
        showLineNumbers: true,
        editorHeight: 400,
      }}
    />
  );
}

Custom Files

import { Sandpack } from "@codesandbox/sandpack-react";

export function CustomPlayground() {
  return (
    <Sandpack
      template="react-ts"
      files={{
        "/App.tsx": {
          code: `import { useState } from "react";
import { Counter } from "./Counter";

export default function App() {
  return (
    <div style={{ padding: 20 }}>
      <h1>Live Counter</h1>
      <Counter initial={0} />
    </div>
  );
}`,
        },
        "/Counter.tsx": {
          code: `import { useState } from "react";

interface CounterProps {
  initial: number;
}

export function Counter({ initial }: CounterProps) {
  const [count, setCount] = useState(initial);
  return (
    <div>
      <button onClick={() => setCount(c => c - 1)}>-</button>
      <span style={{ margin: "0 16px" }}>{count}</span>
      <button onClick={() => setCount(c => c + 1)}>+</button>
    </div>
  );
}`,
          active: true, // This file opens first
        },
      }}
      theme="dark"
      options={{
        showTabs: true,
        showNavigator: false,
        editorHeight: 350,
      }}
    />
  );
}

Custom Sandpack Layout

import {
  SandpackProvider,
  SandpackLayout,
  SandpackCodeEditor,
  SandpackPreview,
  SandpackConsole,
  useSandpack,
} from "@codesandbox/sandpack-react";

// Custom reset button using the useSandpack hook
function ResetButton() {
  const { sandpack } = useSandpack();
  return (
    <button onClick={() => sandpack.resetAllFiles()}>
      Reset
    </button>
  );
}

export function CustomSandpackLayout() {
  return (
    <SandpackProvider
      template="react-ts"
      theme="dark"
      files={{
        "/App.tsx": `export default function App() { return <h1>Hello!</h1>; }`,
      }}
    >
      <div style={{ border: "1px solid #333", borderRadius: 8, overflow: "hidden" }}>
        <div style={{ background: "#1a1a1a", padding: "8px 16px", display: "flex", justifyContent: "flex-end" }}>
          <ResetButton />
        </div>
        <SandpackLayout>
          <SandpackCodeEditor
            showTabs
            showLineNumbers
            showInlineErrors
            wrapContent
          />
          <div style={{ display: "flex", flexDirection: "column", flex: 1 }}>
            <SandpackPreview style={{ flex: 2 }} />
            <SandpackConsole style={{ flex: 1, maxHeight: 120 }} />
          </div>
        </SandpackLayout>
      </div>
    </SandpackProvider>
  );
}

Custom Dependencies

import { Sandpack } from "@codesandbox/sandpack-react";

export function ZustandPlayground() {
  return (
    <Sandpack
      template="react-ts"
      customSetup={{
        dependencies: {
          zustand: "^5.0.0",
          immer: "^10.0.0",
        },
      }}
      files={{
        "/App.tsx": `import { create } from "zustand";
import { immer } from "zustand/middleware/immer";

const useStore = create(
  immer((set) => ({
    count: 0,
    increment: () => set((state) => { state.count++; }),
    decrement: () => set((state) => { state.count--; }),
  }))
);

export default function App() {
  const { count, increment, decrement } = useStore();
  return (
    <div style={{ padding: 20 }}>
      <h1>Zustand + Immer Counter: {count}</h1>
      <button onClick={decrement}>-</button>
      <button onClick={increment}>+</button>
    </div>
  );
}`,
      }}
      theme="dark"
    />
  );
}

Feature Comparison

Feature	Monaco Editor	CodeMirror 6	Sandpack
Bundle size	~5MB gzipped	~50-200kB	~3MB (runtime)
TypeScript IntelliSense	✅ Full LSP	❌ Syntax only	❌ Syntax only
Code execution	❌	❌	✅ Runs in browser
Hot reload preview	❌	❌	✅
Custom languages	✅ TextMate grammars	✅ Lezer grammars	✅ (via CodeMirror)
Accessibility	Basic	✅ Excellent	✅ (via CodeMirror)
Mobile support	⚠️ Limited	✅	✅
SSR-safe	❌ Needs dynamic import	✅	⚠️ Needs dynamic import
React integration	@monaco-editor/react	@uiw/react-codemirror	Native
Diff view	✅ Built-in	Plugin available	No
Multi-file	✅	Via state	✅ Built-in tabs
Custom themes	✅	✅	✅
GitHub stars	38k	7.5k	4k
npm weekly	2M	5M	500k
Maintained by	Microsoft	Marijn Haverbeke	CodeSandbox

When to Use Each

Choose Monaco Editor if:

• Building a browser-based IDE or TypeScript playground
• Need full IntelliSense: hover types, go-to-definition, rename symbol
• Target users are primarily desktop (bundle size acceptable)
• Building something like StackBlitz, TypeScript Playground, or Azure Portal
• Diff editor for code review is needed

Choose CodeMirror 6 if:

• Custom editor in a product (admin SQL editor, config editor, notebook cells)
• Bundle size is important (need to ship fast on mobile)
• Need excellent accessibility (keyboard users, screen readers)
• Building a custom language integration with Lezer grammar
• Embedding a lightweight editor in documentation
• Need fine-grained control over every extension and behavior

Choose Sandpack if:

• Interactive documentation with live code examples
• Tutorial or course platform where learners run code
• React/JavaScript playgrounds (like React's own documentation)
• Prototyping tool where non-technical users modify code
• Blog posts with runnable code examples
• No need to run arbitrary server-side code — browser only

Ecosystem & Community

The in-browser code editor market has three clear tiers of adoption, and each library dominates its niche. Monaco Editor's 38,000 GitHub stars and 2 million weekly downloads reflect its position as the first choice for applications that need VS Code-quality editing. The Microsoft-backed stewardship means long-term maintenance is virtually guaranteed, and the alignment with VS Code's development means Monaco benefits from the billions of dollars invested in VS Code's language server protocols.

CodeMirror 6's ecosystem is perhaps the most technically impressive of the three. Marijn Haverbeke, its creator, is one of the most respected library authors in the JavaScript ecosystem — his work on ProseMirror (the foundation of most modern rich text editors) and CodeMirror has shaped how in-browser editors work. CodeMirror 6's Lezer parser framework, which powers its syntax highlighting, is a distinct contribution to the field — it's a streaming incremental parser that enables highlighting changes without reparsing the entire document. Firefox DevTools, Replit, Jupyter Lab, and the official React documentation all use CodeMirror 6, providing strong social proof.

Sandpack's ecosystem is tied to CodeSandbox's business, which creates a different kind of dependency than open-source maintainer risk. CodeSandbox has a commercial incentive to keep Sandpack functioning and has invested in making it reliable for production documentation use cases. The React team's adoption of Sandpack for react.dev's interactive examples is the strongest endorsement possible — if it's good enough for official React documentation, it's good enough for most use cases.

Real-World Adoption

Monaco Editor powers StackBlitz's cloud development environment, the TypeScript Playground at typescriptlang.org, GitHub's Web Editor (the . shortcut on any repo), and Azure Portal's code editing features. This enterprise-scale usage validates Monaco's reliability for high-traffic, mission-critical applications. The challenge is that all of these implementations required significant engineering effort to handle Monaco's bundle size, worker configuration, and SSR requirements.

CodeMirror 6 is embedded in products where the editor is a component within a larger application rather than the main feature. Database administration tools (Prisma Studio, multiple SQL clients), documentation platforms, notebook environments (Observable), and developer tools dashboards use CodeMirror because it composes well with existing React applications without dramatically increasing bundle size.

Sandpack's most visible adoption is react.dev, where every interactive code example uses Sandpack. This production deployment at global scale with massive traffic has stress-tested Sandpack's reliability. The CodeSandbox team has also deployed Sandpack in their own main product, giving it the benefit of real-world dogfooding by its creators.

For documentation platforms that embed live code examples, the choice of in-browser editor often intersects with the documentation tool itself — Mintlify vs Fern vs ReadMe developer documentation 2026 covers how each documentation platform handles code playgrounds and SDK examples.

Developer Experience Deep Dive

Monaco's developer experience for the editor itself is excellent once you've solved the initial setup challenges. The @monaco-editor/react wrapper handles most of the complexity, and the TypeScript types are comprehensive. The challenging parts are worker configuration (Monaco needs web workers for language services), SSR handling (Monaco must be dynamically imported in Next.js), and bundle size management. Teams that use Monaco consistently report that the initial setup investment is front-loaded — once it's working, adding features is straightforward.

CodeMirror 6's developer experience rewards investment in understanding its state management model. The extension system is genuinely powerful but requires learning the CodeMirror 6 mental model (transactions, state fields, view plugins). The payoff is a library that can be customized to virtually any requirement. The documentation is thorough but dense. The community on GitHub and Discord is knowledgeable and responsive.

Sandpack's developer experience is the friendliest for getting started quickly. The <Sandpack> component with a template and files is all you need for a basic playground. The SandpackProvider + individual components approach scales to complex layouts. The main challenge is understanding Sandpack's limitations — it's a browser runtime, not a Node.js runtime, so server-side features, file system operations, and arbitrary npm packages that use Node.js-specific APIs won't work.

The animation and styling libraries a team chooses also affect which editor integration feels most natural — Framer Motion vs Motion One vs AutoAnimate 2026 shows how animation libraries are often demoed through interactive playground patterns that benefit from Sandpack's live execution.

Performance & Benchmarks

Monaco's initialization time is the most significant performance consideration. Loading the full Monaco bundle (2-5MB gzipped) adds 1-3 seconds to first-interactive time on typical connections. Dynamic imports and loading states mitigate the user-visible impact, but the network cost is real. Once loaded, Monaco's editing performance is excellent — the VS Code team has heavily optimized it for large files and complex operations.

CodeMirror 6's initialization is near-instantaneous for most configurations — the minimal bundle loads and renders in under 100ms. For large documents (100,000+ lines), CodeMirror 6's incremental parsing ensures syntax highlighting updates are fast. The performance ceiling is high: Jupyter Lab notebooks with many cells use CodeMirror 6 without performance concerns.

Sandpack's initialization involves loading the browser runtime (Nodebox or the legacy sandboxed iframe approach), which takes 2-5 seconds on first load. Subsequent navigations use a cached runtime. The execution performance for React applications is good — hot reload is typically under 500ms for small code changes.

Migration Guide

Migrating from older CodeMirror versions (5.x) to CodeMirror 6:

CodeMirror 6 is a complete rewrite with a different API. You cannot incrementally migrate — it's a full replacement. The migration requires rewriting all editor initialization code and any custom extensions. The new API is more powerful and composable but requires learning the extension model from scratch.

Adding Monaco to an existing Next.js application:

The key steps are: add @monaco-editor/react, use next/dynamic with ssr: false to lazy load the component, configure webpack if needed for Monaco's web workers, and ensure Monaco loads after the page is interactive. The @monaco-editor/react package handles most of the worker configuration automatically, but complex setups may need the MonacoEnvironment.getWorkerUrl configuration.

Replacing a static code display (highlight.js/Prism) with an interactive editor:

This is the most common entry point for all three libraries. Start with CodeMirror 6 using @uiw/react-codemirror for the simplest upgrade path from static highlighting to an interactive editor. If you later need execution, add Sandpack. If you need IntelliSense, migrate to Monaco.

Final Verdict 2026

The in-browser editor space has a clear decision tree. If users need to run the code, use Sandpack. If you need TypeScript IntelliSense for a developer-facing product, use Monaco. For everything else — SQL editors, config editors, documentation editors, lightweight code input — use CodeMirror 6.

The most common mistake is reaching for Monaco when CodeMirror 6 would serve the use case better. Monaco's bundle overhead is significant, and for use cases that don't require IntelliSense, it's substantial overhead for minimal benefit. Evaluate your actual requirements honestly before committing to Monaco's complexity.

Methodology

Data sourced from Monaco Editor documentation (microsoft.github.io/monaco-editor), CodeMirror 6 documentation (codemirror.net), Sandpack documentation (sandpack.codesandbox.io), npm weekly download statistics as of February 2026, GitHub star counts as of February 2026, and bundle size measurements from bundlephobia.com and direct testing.

Related: Best Markdown Parsing Libraries 2026, Best AI LLM Libraries JavaScript 2026, Best React Component Libraries 2026