As a Middle Java Backend Developer, you will be instrumental in expanding a US-based B2B platform. Your responsibilities include developing, implementing, and maintaining backend services using Java and the Spring framework. You'll design and optimize RESTful APIs, collaborate with cross-functional teams to deliver technical solutions, and leverage AWS services like EC2, S3, Lambda, RDS, SNS, and SQS for cloud-based application management. You will ensure performance, scalability, and reliability through testing and monitoring while contributing to architecture decisions and code reviews. This role requires a solid understanding of microservices architecture and design patterns.