Extension Build Benchmark

This repository benchmarks four browser extension frameworks by building the same extension with identical functionality. The goal is to compare dev startup time, build time, and output size.

Reference: rstackjs/build-tools-performance

Frameworks

Directory	Framework	Version	Bundler	Description
addfox/	Addfox	0.2.0	Rsbuild 2.0.7	Rsbuild-based framework (addfox.config.ts, defineConfig + pluginReact)
wxt/	WXT	0.20.26	Vite 8.0.14	WXT framework
plasmo/	Plasmo	0.90.5	Parcel 2.9.3	Plasmo framework
extensionjs/	Extension.js	3.17.0	Rspack 2.0.x	Extension.js framework

Benchmark Results

Environment

• OS: Windows
• Browser: Microsoft Edge
• Node.js: 24.16.0
• Package Manager: pnpm 10.0.0
• Test Method: 5 runs per framework, averaged (warm-up run before each suite to eliminate cold-start bias)
• Last Updated: 2026-05-29

Dev Startup Time

Time from running dev command to dev server ready (including browser launch and extension installation where applicable):

Note: All frameworks automatically open the browser and install the extension during dev. Each framework was tested with 5 runs after a warm-up run to eliminate cold-start bias.

Framework	Average	Min	Max	Runs
Extension.js	2.10s	2.07s	2.13s	2.07, 2.10, 2.13, 2.12, 2.10
WXT	2.18s	2.07s	2.46s	2.46, 2.15, 2.11, 2.07, 2.09
Addfox	2.41s	2.33s	2.64s	2.36, 2.33, 2.64, 2.35, 2.35
Plasmo	3.02s	2.99s	3.05s	3.01, 3.01, 3.05, 3.03, 2.99

Build Time

Time to complete production build (total time from running the command to build complete, including CLI startup overhead):

Framework	Average	Min	Max	Runs
Addfox	1.44s	1.43s	1.45s	1.43, 1.44, 1.43, 1.45, 1.45
Extension.js	1.52s	1.51s	1.54s	1.54, 1.52, 1.52, 1.51, 1.52
WXT	1.82s	1.80s	1.83s	1.82, 1.83, 1.82, 1.83, 1.80
Plasmo	2.62s	2.58s	2.69s	2.69, 2.65, 2.58, 2.58, 2.61

Build Output Size

Production build output (excluding source maps):

Framework	Size	Target
WXT	812 KB	chrome-mv3
Addfox	837 KB	extension-chromium
Plasmo	1.36 MB	chrome-mv3-prod
Extension.js	1.45 MB	chromium (no source maps; chrome/edge builds are ~20 MB each with source maps)

Measurement method: Output directory is cleaned before each build. Size is the exact sum of all file bytes in the production output directory (source maps excluded).

Summary

Framework	Version	Dev Startup	Build Time	Output Size
Extension.js	3.17.0	🥇 2.10s	🥈 1.52s	🥉 1.45 MB
WXT	0.20.26	🥈 2.18s	🥉 1.82s	🥇 812 KB
Addfox	0.2.0	🥉 2.41s	🥇 1.44s	🥈 837 KB
Plasmo	0.90.5	4th 3.02s	4th 2.62s	4th 1.36 MB

Unified Tech Stack

• Framework: React + Tailwind CSS 3
• Dependencies: lodash, react, react-dom, webextension-polyfill
• Entry Points: background, content, options, popup, sidepanel, devtools, space (custom)
• Features:
  • Popup: Capture screenshot of current page
  • Sidepanel: Fake AI chat (fixed responses)
  • DevTools: Display captured element colors
  • Space: Display captured screenshots (temporary storage)
  • Options: Common settings UI (language, limits, permissions)
• Resources: Icons from VideoRoll-Pro, i18n via _locales (en / zh_CN)

Usage

1. Install Dependencies

pnpm install --no-frozen-lockfile

2. Copy Icons

Requires VideoRoll-Pro repository:

pnpm run copy-icons

3. Run Individual Tests

Dev startup time:

pnpm run test:addfox
pnpm run test:wxt
pnpm run test:plasmo
pnpm run test:extensionjs

Build time:

pnpm run build:addfox
pnpm run build:wxt
pnpm run build:plasmo
pnpm run build:extensionjs

4. Batch Benchmark (5 runs with average)

# Dev benchmark
node scripts/run-benchmark-suite.mjs dev

# Build benchmark
node scripts/run-benchmark-suite.mjs build

Directory Structure

benchmark/
├── package.json               # Root scripts: copy-icons, test:*, build:*
├── pnpm-workspace.yaml        # Workspaces: addfox, wxt, plasmo, extensionjs
├── scripts/
│   ├── dev-benchmark.mjs      # Dev startup time benchmark
│   ├── build-benchmark.mjs    # Build time benchmark
│   ├── run-benchmark-suite.mjs # 5-run benchmark suite with averages
│   ├── batch-benchmark.mjs    # Batch test all frameworks
│   └── copy-icons.mjs         # Copy icons from VideoRoll-Pro
├── shared/
│   ├── icons/                 # Shared icons
│   └── locales/               # i18n reference
├── addfox/                    # Addfox implementation
├── wxt/                       # WXT implementation
├── plasmo/                    # Plasmo implementation
└── extensionjs/               # Extension.js implementation

Implementation Status

• ✅ Addfox: Fully implemented with all features
• ✅ WXT: Fully implemented with all features
• ✅ Extension.js: Fully implemented with all features
• ✅ Plasmo: Fully implemented with all features