Backend Developer

We are seeking a Senior Java Backend Developer to join a dynamic engineering team supporting a large retail client in Pleasanton, CA. This onsite, six-month contract role offers the opportunity to build scalable backend solutions, contribute to microservices architecture, and help drive technical excellence across a collaborative product and engineering environment. Responsibilities

• Design, build, and maintain high-performing backend services using Java and Spring Boot.
• Contribute to microservices architecture and participate in system design discussions.
• Develop clean, well-structured, and maintainable code aligned with engineering best practices.
• Create and optimize database schemas, queries, and stored procedures for performance and scalability.
• Partner with product, QA, DevOps, and frontend teams to deliver reliable solutions.
• Perform code reviews and provide thoughtful feedback to support quality and consistency.
• Investigate, troubleshoot, and resolve complex production issues in a timely manner.
• Mentor junior and mid-level developers and contribute to technical growth across the team.
• Support architecture planning, technical roadmaps, and improvements to CI/CD and DevOps practices.
• Help ensure applications meet standards for security, reliability, and scalability.

• 10+ years of professional Java development experience.
• Strong hands-on experience with Spring Boot and Spring Framework, including Spring MVC, Spring Data, and Spring Security.
• Proven background in building and supporting microservices-based systems.
• Deep experience with relational databases such as MySQL, PostgreSQL, or Oracle, including schema design and query optimization.
• Solid understanding of RESTful API design and development.
• Experience with Hibernate/JPA and ORM-based development.
• Working knowledge of Git, Maven or Gradle, and unit testing tools such as JUnit and Mockito.
• Strong problem-solving, analytical, and communication skills.
• Ability to work collaboratively across cross-functional teams in a fast-paced environment.
• Bachelor’s or master’s degree in Computer Science, Engineering, or a related field, or equivalent practical experience.

Preferred Skills

• Experience with NoSQL technologies such as MongoDB, Redis, or Cassandra.
• Exposure to Docker and Kubernetes.
• Familiarity with message queuing platforms such as Kafka or RabbitMQ.
• Experience with cloud platforms such as AWS, Azure, or GCP.
• Knowledge of event-driven architecture and Agile/Scrum practices.
• Background in technical leadership, coaching, or mentoring.
• Experience with performance tuning and monitoring tools such as New Relic, Datadog, or Splunk.
• Familiarity with CI/CD tools such as Jenkins or GitLab CI.
• Experience working in a product-focused, collaborative engineering organization.

Horizontal is committed to fostering an inclusive workplace where diverse perspectives are valued, respected, and empowered to contribute. We believe equity and belonging strengthen teams, improve innovation, and help create better outcomes for everyone.