The `dependencies` and `devDependencies` properties in the `package.json` file are used to manage different types of dependencies in a Node.js project. Here's the difference between them: 1. `dependencies`: - The `dependencies` property is used to list the packages that are required for the project to run in a production or deployment environment. - These packages are necessary for the application's core functionality and are typically required at runtime. - When you install the project dependencies using `npm install`, the packages listed in the `dependencies` section are installed. Example: 

   "dependencies": {
     "express": "^4.17.1",
     "lodash": "^4.17.21"
   }
2. `devDependencies`: - The `devDependencies` property is used to list the packages that are only required during development, such as testing frameworks, build tools, and development-specific utilities. - These packages are not necessary for the application to run in a production environment but are helpful during development and testing phases. - When you install the project dependencies along with dev dependencies using `npm install`, the packages listed in both the `dependencies` and `devDependencies` sections are installed. Example: 
   "devDependencies": {
     "mocha": "^9.0.3",
     "nodemon": "^2.0.13"
   }
By separating dependencies into `dependencies` and `devDependencies`, you can distinguish between packages required for production and those required for development. This separation helps reduce the size of the production deployment by excluding unnecessary development-related packages. Conclusion To summarize, `dependencies` includes packages needed for the application to run in a production environment, while `devDependencies` includes packages required during development and testing but are not necessary for the production deployment.