Well-designed APIs are a joy to use; poorly-designed APIs are cumbersome, confusing and frustrating, just like everyday things. Would you buy a Kitchen Radar 3000? Are you able to use any washing machine instantly without reading user manual? Why QWERTY layout was invented? Like everyday things, APIs must have a clear purpose, must be used easily by anyone and are constrained by their environment. During this session Arnaud Lauret, the API Handyman, makes a parallel between everyday things design and API design in order to expose simple but fundamentals API design principles.