I'm on windows with CMD. This is my package.json: { "name": "my-app", "scripts": { "start": "cross-env NODE_ENV=dev node src/index.js", "playground": "graphcool playground" }, "dependencies": { "graphcool-binding": "1.3.5", "graphql-yoga": "^1.1.7" }, "devDependencies": { "cross-env": "^5.1.3", "graphcool": "1.0.0-beta4.1.1" } }