This is a great post, and DDB is a great database for the right use cases. I want to give a shout out to FaunaDb to anybody looking for alternatives - its also serverless and crazy scalable, and usage-based pricing. Its downside is its proprietary FQL query language, not because it sucks (it doesn't!) but there is a learning curve. They provide a rich GraphQL interface as an alternative to FQL. Its upside vs DDB is a much richer set of functions including aggregations, and first-class support for user defined functions. Their attribute-based permissions system is phenomenal. Its definitely worth a look if you're considering DynamoDb but want something that takes less upfront planning about access patterns.