Today, engineered three-dimensional tissue models from human cells of the skin, cornea, mucosa, and respiratory tract are widely used in pharmaceutical, chemical, consumer, and cosmetic industries as alternatives to animal testing. The currently available scientifically valid 3D tissue-engineered models, however, are protected by patents and/or are being commercialized using proprietary tissue culture procedures owned by only a few private companies. As a consequence, their continued commercial availability might not be guaranteed in the long-term. In collaboration with its partners, the ALEXANDRA Association strives to ensure a long-term, sustainable, and global implementation of alternative methods based on nonprofit, patent-free, and proprietary-free development of ''open source'' (OS) human tissue engineering technologies. By doing so, the association proposes a new standard in 3D tissue reconstruction as a basis for animal-free testing method implementation by supporting the development, production, validation, and technology transfer based on a global OS concept.