# what's v3 really means? ([Course] API design in Node with Express v3) > in `package.json` file, I found express is using version 4.x, that's very confused me! Maybe, it means the tutorials version 3? https://github.com/FrontendMasters/api-design-node-v3/blob/master/package.json ```js // "express": "^4.16.4", ```