Experiment Execution Engine (EEE) eases the development of IoT applications that perform analysis of recent or continuously increasing volumes of IoT data from various data stores. To this end, EEE provides APIs for scheduling queries on federated large-scale semantically-enabled IoT data stores. Queries are expressed in the FIESTA-IoT Experiment Description Specification (FEDSpec), which acts as a Domain Specific Language (DSL). EEE (in combination with Experiment Management Console - EMC) further provides features such as (a) manage scheduled experiments, (b) (un)subscribe to already existing FEDSpec objects, (c) execute an on-demand query outside a described schedule, (d) monitor execution logs, (e) interact with third-party services such as Analytics and Result Storage, (e) handle dynamic attributes, and (f) API sandbox. EEE is integrated within the FIESTA-IoT Platform. It can be customised depending on needs.