Automation efforts in libraries have moved from standalone database systems to cloud-based systems, traversing generations of library management system (LMS) and integrated library management system (ILS) in between. This paper attempts to traverse this transition with emphasis on present-day technological state-of-affairs in the libraries. The traditional terminologies vis-a-vis the cloud associated architecture has been touched upon. The paper introduces library specific tenant- based software services over the cloud architecture and also the associated maturity model. Apart from ILS, other facets of library automation have been talked upon with examples from libraries providing such aggregation or dissemination services. The paper lays special emphasis on library service platforms in use in India. An internet search was done to locate the cloud- based library software in use and thereafter a listing of major vendors and providers promoting these software were made. Questionnaires were sent to such vendors and exploratory study was conducted to overcome the non-respondent bias and the usage statistics extracted. Koha was found to be the most common open source in use over the cloud through a paid support from three of the eleven vendors in India. Only two clouds- enabled proprietary software are available at present, e-Granthalaya and Cybrarian TM with former having the support from Government and hence has more installations. A detailed analysis on suitability of an ILS for a library indicated that single-tenant SaaS model suits large libraries while small group of homogeneous libraries can do with multi-tenet SaaS model. Still, library SaaS is in its infancy in India. http://dx.doi.org/10.14429/djlit.35.6.8895