To realise the full potential of a FAIR ecosystem in which research can be easily shared and optimally reused, as put forward in the Turning FAIR into reality report, we must look beyond ‘just’ research data: on the one hand we should include research software and other digital objects, and on the other hand we should lay out a vision and a roadmap for services and supporting infrastructure that fosters an optimal interplay between digital objects and services. The latter calls for an assessment framework for service owners which can be used to gauge where change is needed, together with actionable recommendations to drive incremental improvements. However, while the development of various FAIR assessment frameworks for data and other digital objects has enjoyed substantial activity over the last few years, a FAIR assessment framework for data services is still lacking — a fact that was recently underlined again in the interim recommendations from the EOSC FAIR Working Group. FAIRsFAIR task 2.4, entitled ‘FAIR services’, aims to close this gap by developing a FAIR assessment framework for data services (alongside a similar framework for research software). This report marks the first milestone of the task. It presents a survey of existing FAIR assessment frameworks, a proposed set of guiding principles and desiderata for the FAIR assessment framework that will be constructed, and three ‘FAIR service assessment’ case studies. We are seeking wide feedback on this report to inform subsequent work and, ultimately, feed into a FAIR assessment framework for data services that delivers clear direction and value to service owners and the community at large. Feedback and suggestions will be most welcome as comments on the public Google Doc version of this report: https://docs.google.com/document/d/1VO8T8mpsp4qt-XSbcdUBTMVgOVwEf9na81Ccv56NPg4/edit