Before will look at the difference, it is IMPORTANT to understand the difference between dependencies and devDependencies.

devDependencies are for the development-related scripts, e.g. unit testing, packaging scripts, DOCUMENTATION generation, etc. where dependencies are required for production USE, and assumed required for dev as well. As for example, you can include some plugin which you require during development like (for debugging or unit testing) but you don’t need them on production.

So --save adds packages under dependencies and --save-dev adds under devdependencies SECTION.

1. {
2. "name": "my-project-name",
3. "version": "0.1.0",
4. "dependencies": {
5. "grunt": "~0.4.5",
6. "grunt-contrib-nodeunit": "~0.4.1",
7. "grunt-contrib-uglify": "~0.5.0"
8. }
9. "devDependencies": {
10. "grunt": "~0.4.5",
11. "grunt-contrib-jshint": "~0.10.0",
12. }
13. }

Before will look at the difference, it is important to understand the difference between dependencies and devDependencies.

devDependencies are for the development-related scripts, e.g. unit testing, packaging scripts, documentation generation, etc. where dependencies are required for production use, and assumed required for dev as well. As for example, you can include some plugin which you require during development like (for debugging or unit testing) but you don’t need them on production.

So --save adds packages under dependencies and --save-dev adds under devdependencies section.