This paper introduces Q8bot, an open-source, miniature quadruped designed for robotics research and education. We present the robot's novel zero-wire design methodology, which leads to its superior form factor, robustness, replicability, and high performance. With a size and weight similar to a modern smartphone, this standalone robot can walk for over an hour on a single battery charge and survive meter-high drops with simple repairs. Its 300-dollar bill of materials includes minimal off-the-shelf components, readily available custom electronics from online vendors, and structural parts that can be manufactured on hobbyist 3D printers. A preliminary user assembly study confirms that Q8bot can be easily replicated, with an average assembly time of under one hour by a single person. With heuristic open-loop control, Q8bot achieves a stable walking speed of 5.4 body lengths per second and a turning speed of 5 radians per second, along with other dynamic movements such as jumping and climbing moderate slopes.