Basic

{
  "name": "expo",
  "description": "My package",
  "version": "0.1.0",
  "license": "MIT",
  "keywords": ["http", "server"],
  "author": "Rico Sta. Cruz <rstacruz@users.noreply.github.com>",
  "engines": {
    "node": ">=0.8.0"
  },
  "main": "index",
  "bin": {
    "command": "./bin/command"
  },
  "repository": {
    "type": "git",
    "url": "https://github.com/rstacruz/___.git"
  },
}

Highlighted lines are required.

Dependencies

"dependencies": {
  "colors":   "*",
  "flatiron": "0.1.x",
  "flatiron": "~0.1.0",
  "plates":   "https://github.com/user/project/tarball/branch",
  "stuff":    "git://github.com/user/project.git#commit-ish"
},

"devDependencies": { ··· },
"peerDependencies": { ··· },
"optionalDependencies": { ··· },

See Semver cheatsheet for explanation of version ranges.

Scripts

"scripts": {
  "start": "node ./bin/xxx",       /* npm start */
  "test": "vows --spec --isolate", /* npm test */
  "postinstall": "...",
  "prepublish": "grunt build",     /* after 'npm install' and before 'npm 
                                      publish' */
}

Misc

"private": true,
"preferGlobal": true

Config

{
  "config": {
    "foobar": "hello"
  },
  "scripts": {
    "run": "echo $npm_package_config_foobar"
  }
}

Keys in config are exposed as env vars to scripts.

References