1.What is AWS?
2.Why AWS account is needed when developing Alexa skill?
According to Amazon's requirements, Alexa skill uses the smart home model and includes code in an AWS Lambda function to provide communication between Alexa and device.
For more details, please refer to Alexa official website:https://developer.amazon.com/en-US/docs/alexa/smarthome/understand-the-smart-home-skill-api.html#how-the-smart-home-api-works
So Tuya will use AWS account when developing and subsequently maintaining Alexa skill for you.
3.Why might AWS incur charges?
Amazon provides monthly free tier for AWS Lambda, it includes one million free requests per month and 400,000 GB-seconds of compute time per month. If the usage of Alexa skill exceeds the free tier, the fee will be based on the number of requests per month and the computing time of each request. For more details, please refer to AWS official website:https://aws.amazon.com/lambda/pricing/?nc1=h_ls