Sr. Back End Developer

We’re looking for a Senior Back End Developer to help build and support the next generation of a high-scale web platform focused on billing and financial accuracy. This role offers the opportunity to work on meaningful, cross-functional projects spanning Java/Spring applications, REST services, cloud technologies, and distributed systems in an agile environment. Responsibilities

• Develop and enhance Java and Spring-based web applications that support billing and reporting capabilities
• Contribute to the full software development lifecycle, from design and implementation through testing and production support
• Refactor and improve existing systems quickly and thoughtfully to support scalability and performance
• Build and maintain RESTful services and integrate with internal platforms and downstream systems
• Partner with cross-functional teams to translate high-level ideas into user stories, tasks, and technical solutions
• Participate in agile practices such as test-driven development, pair programming, and collaborative design discussions
• Support database and Kafka-related development, including troubleshooting and performance tuning
• Work closely with DevOps and production support processes to help monitor and improve application health
• Contribute to the development of scalable solutions for high-volume, distributed environments

• 7-10 years of experience in application software development
• Strong hands-on experience with Java and Spring
• Proven ability to design, build, and consume REST services
• Solid understanding of object-oriented programming and design patterns
• Experience with test-driven development and strong unit testing practices
• Comfort working in Unix/Linux command line environments
• Experience with database development, debugging, and optimization
• Working knowledge of Kafka in development and troubleshooting scenarios
• Ability to collaborate effectively in an agile, team-oriented environment

Preferred Skills

• Experience with Groovy and Maven
• Background in large-scale distributed systems and client-server architectures
• Familiarity with emergent design and pair programming
• Experience supporting production systems in a DevOps-oriented environment
• Ability to break down high-level technical discussions into clear, actionable work items
• Interest in cloud technologies, infrastructure automation, and SOA-based web applications

Horizontal is committed to creating an inclusive environment where people of all backgrounds can thrive. We value diversity, equity, and inclusion as essential to building strong teams, better ideas, and meaningful outcomes.