Phil Day presented on Configured Things' data gateway for filtering real-time IoT sensor data using declarative policies. The gateway ingests data through MQTT or HTTPS and applies user-defined policies in Flux to control data visibility, quality, and filtering. Policies can dynamically define data scopes, quality metrics like aggregation, and filters. The policies are mapped to Flux queries to process the data in InfluxDB. This allows different stakeholders to securely access customized data streams from sensors in applications like smart cities.