AWS Lambda provides high scalability due to being serverless and stateless, allowing many copies of the lambda function to be spawned instantaneously (as described here ). However, when writing application code, you are likely to want access to some stateful data. This means connecting to a datastore such as an RDS instance or S3. However, connecting to other services from AWS Lambda adds time to your function code. There may also be side effects from high scalability such as reaching the maximum number of allowed connections to an RDS instance. One option to counter this is to use container reuse in AWS Lambda to persist the connection and reduce lambda running time.