By the documentation from AWS - http://docs.aws.amazon.com/sns/latest/dg/SendMessageToHttp.html , SNS would send messages to HTTP/HTTPS endpoint in JSON format. But current implementation of `moto` sends messages in form-data format.
By the documentation from AWS - http://docs.aws.amazon.com/sns/latest/dg/SendMessageToHttp.html , SNS would send messages to HTTP/HTTPS endpoint in JSON format. But current implementation of `moto` sends messages in form-data format.