This deposit contains a preprint of a poster paper, and the poster itself, for "Federated Function as a Service for eScience" as submitted and peer-reviewed by the 17th IEEE International Conference on eScience (eScience 2021), presented virtually 22 September 2021. Abstract: The function as a service paradigm aims to abstract the complexities of managing computing infrastructure for users. While adoption in industry has been swift, we have yet to see widespread adoption in academia. This is in part due to barriers such as the need to access large research data, diverse hardware requirements, monolithic code bases, and existing systems available to researchers. We describe funcX, a federated function-as-a-service platform that addresses important requirements for use of FaaS in research computing. We outline how funcX has been used in early science deployments.