AWS API Gateway with HTTP, Lambda, DynamoDB, and iOS
AWS can be used to create a variety of features on the server side. Many of those can work together and create an entire online set of storage and functionality with little-to-no code.
Check out this course and see how Lambda (serverless functions) can be run to interact with DynamoDB for database storage online.
Not only that but the API Gateway can be used to hit servers, mocks (hardcoded responses) and Lambda functions.
Plus, the various SDK needs for your mobile/iOS app can be generated for you including model classes and API files based on the Swagger YAML files exported from your API definition!