Which Amazon service offers a NoSQL database solution suitable for rapidly growing applications?

Amazon DynamoDB is the service that offers a NoSQL database solution optimal for rapidly growing applications. This choice is ideal because DynamoDB is designed for high scalability and performance, capable of handling large amounts of data and high request rates seamlessly. It provides the ability to quickly scale up or down to accommodate fluctuating workloads without the need for manual intervention, making it well-suited for applications that expect growth or variable loads.

DynamoDB also features a fully managed service structure which allows developers to focus on building applications rather than managing the underlying infrastructure. In addition, it offers built-in security, in-memory caching with DynamoDB Accelerator (DAX), and global tables for multi-region, fully replicated data.

In contrast, other services like Amazon S3 are primarily for object storage rather than database solutions, making them unsuitable for handling structured NoSQL data. Amazon RDS and Amazon Aurora are relational database services that are better suited for structured data and require fixed schemas, which do not meet the needs of all applications, especially those that require high levels of flexibility and rapid data access.