Advanced endoscopic therapeutic techniques, such as endoscopic mucosal resection, endoscopic submucosal dissection, and third-space endoscopy, have transformed digestive endoscopy into a minimally invasive surgical platform. This transformation, nonetheless, poses a major challenge, namely the safe and efficient closure of the postoperative gastrointestinal (GI) defects that arise, as inadequately closed defects may lead to serious postoperative complications. This review provides a comprehensive overview of the historical background, the basic principles of closure, and the technical changes of the mainstream devices used for closure of GI defects, viewed mostly from the perspective of medical devices and engineering design. We have divided the most significant closure devices currently in use into endoscopic clipping devices and endoscopic suturing devices, and we have outlined their respective historical development and working principles. In addition, this review has identified and explained advanced clip-based closure methods that employ multiple through-the-scope clips (TTSCs) or are combined with auxiliary devices to overcome the inherent limitations of single-TTSC use. This review aims to provide endoscopists with a deeper understanding of the existing closure devices so as to  facilitate their optimal clinical use, and to offer insights that may help in the development of next-generation closure technologies.