Various accessibility standards and guidelines exist, targeting different disabilities. Nonetheless persons suffering from Severe Motor Disabilities (SMD) are generally excluded from development efforts, mainly because of a lack in accessibility regulations, standards and developer support. This work presents Butterfleye, a novel developer-centric tool that facilitates the development of accessible gaze-driven web applications for SMD users. Butterfleye relies and builds upon a widely-adopted open-source front-end framework to incentivise frictionless developer adoption. Low cost eye-tracking devices are also examined to lower barriers for end-user adoption.We present an open-source library developed iteratively over a series of user-centric studies and report initial evidence of, and observations on, its effectiveness with SMD users.