The term “sharing economy” is intended to identify a set of social relations, digitally mediated, based on the principles of reciprocity and trust. However, such principles must result from the technological and design requirements of the platforms used where users deposit their personal data, insert information about interests and daily practices, communicate with strangers and, in this way, create personal bonds. The study hereby presented aims to identify a set of guidelines for building trust in the context of digitally mediated sharing of collaborative lifestyles, on platforms that promote the sharing of experiences in sustainable contexts. Within the scope of this study, sharing collaborative lifestyles means a non-monetary social exchange of knowledge, skills, accommodation, and food. The analyzed platforms — Volunteers Base, The Poosh, and WWOOF Portugal — are non-commercial organizations that promote experiences in educational projects in eco villages, natural construction projects in rural areas, permaculture projects on farms, among others. A multi-case and documentary study of the terms and policies published by these digital platforms was carried out. These regulatory documents were submitted to content analysis, using the Iramuteq and MAXQDA software. From this analysis, 20 guidelines emerged, in three categories: “practices and conduct”, “conditions” and “security and privacy”, which can guide users and platforms in the construction of digitally mediated sharing relationships in a transparent and reliable way.