Phonebloks is an open-source modular smartphone concept created and designed by the Dutch designer Dave Hakkens in 2013, primarily to reduce electronic waste. While Phonebloks is not the first attempt at modular design in a phone, it is notable due to the extent of its modularity and the attention and support it has garnered. By attaching individual third-party components (called "bloks") to a main board, a user would create a personalized smartphone. These bloks can be replaced at will to replace a broken blok, to upgrade an existing blok, or to expand the functionality of the phone into a specific direction. Bloks would be available in Blokstore, "an app store for hardware", where users could buy new and used bloks as well as sell back their old ones.
There is no plan to actually produce the Phonebloks design as a commercial product, but Hakkens and the Phonebloks web site have partnered with Project Ara at Google, which aims to commercialize a different modular smartphone design.