A Lightweight SMTP Server for High-Performance Email Processing with AMQP Integration

Abstract

This paper introduces the Lightweight SMTP Server (LSMTP), a minimalistic SMTP server designed for modern distributed systems that require high scalability and efficiency. LSMTP is optimized to handle the essential SMTP commands—HELO/EHLO, MAIL FROM, RCPT TO, DATA, and QUIT—while excluding advanced features like encryption, spam filtering, and email storage. This streamlined approach makes LSMTP ideal for use cases where basic email reception and forwarding are needed, such as in microservices architectures. The server is implemented using the Rust programming language and the Tokio asynchronous runtime, ensuring optimal performance and minimal resource consumption. Integrated seamlessly with AMQP (Advanced Message Queuing Protocol), LSMTP forwards incoming emails to message brokers like RabbitMQ for further processing, such as analytics or archiving. The results of our performance benchmarks highlight LSMTP's superior efficiency compared to traditional mail servers, making it a highly suitable solution for lightweight, high-performance email processing in distributed environments.