Amazon DynamoDB is a fully managed, multi-region, serverless database that supports key-value and document data models, making it suitable for a wide variety of applications. Being serverless, it automatically scales to accommodate the workload. Amazon RDS is relational and not primarily serverless, although it has some auto-scaling features. Amazon Aurora is a relational database and, while it offers serverless options, it does not support non-relational data models. Amazon Redshift is a data warehousing service and does not offer a serverless, non-relational database.