At 10am on Black Friday, your phone rings: the new JS application you deployed came under too much load, and the site has gone down! Your employer is losing sales opportunities... your employer is losing money! But you don’t lose your cool. You log into your cloud provider and tweak your autoscaling settings. Now the deployment can handle the load spike but with four times the number of servers, which is four times the cost. The next day, you try to analyze what happened and begin to optimize your application to prepare for future load spikes. This talk is a journey into the world of Node.js performance, taking a look at the available tools and optimization techniques inspired by insight gained from glimpsing under the hood of Node and V8.