Mature apps face problems with abusive requests like misbehaving users, malicious hackers, and naive scrapers. Too often they drain developer productivity and happiness. Rack::Attack is middleware to easily throttle abusive requests. At Kickstarter, we built it to keep our site fast and reliable with little effort. Learn how Rack::Attack works through examples from kickstarter.com. Spend less time dealing with bad apples, and more time on the fun stuff.