AWS IoT Core is a managed service that allows users to easily connect and manage Internet of Things (IoT) devices. It uses the MQTT protocol, which is lightweight and fault-tolerant, and can be used as a message broker or with message routing functionality to forward messages to other Amazon Web Services such as Kinesis, SQS, and Kafka. AWS IoT Core can be integrated with AWS Lambda functions, allowing users to trigger actions based on incoming MQTT messages. In this example, an AWS Lambda function is created to insert MQTT messages into a Timescale database, which is a time-series database that allows for fast ingestion and querying of data in milliseconds, even at terabyte scale. The function uses PostgreSQL's NOW() function to timestamp the inserted data, and the process is demonstrated by creating a message routing rule and testing it with a Python script.