An AWS SNS (Simple Notification Service) developer designs, deploys, and manages communication systems on the Amazon Web Services platform. They create topics for high-throughput, push-based, many-to-many messaging using SNS to distribute messages to multiple subscribing endpoints. They handle tasks like sending individual messages or to fan-out messages to large numbers of recipients for parallel processing. They also work on system-to-system messaging with microservices, distributed systems, and serverless applications. Furthermore, they ensure message security and privacy by managing permissions and encrypting the messages. Regular monitoring, troubleshooting, and optimizing performance of the SNS service are also part of their responsibilities.