What is the difference between devDependencies and dependencies in package.json?

 

🔹 dependencies

Packages your app needs to run in production.

• Used in the app's runtime code

• Installed on both development and production environments

• Example: Frameworks, HTTP clients, database drivers

Example:

"dependencies": {
  "express": "^4.18.2",
  "axios": "^1.6.0"
}

---

🔸 devDependencies

Packages your app only needs during development (not in production).

• Used only for building, testing, linting, compiling

• Installed only in development, not in production (NODE_ENV=production)

• Example: TypeScript, Webpack, ESLint, test libraries

Example:

"devDependencies": {
  "typescript": "^5.4.0",
  "eslint": "^8.54.0",
  "jest": "^29.7.0"
}

---

	Dev (write code)	Build (transpile/bundle)	Run (prod server)
dependencies	✅	✅	✅
devDependencies	✅	✅	❌