Principal Software Engineer

12+ years of professional software development experience, with deep expertise in Java and/or Go (both preferred). Hands-on experience with a major cloud platform (GCP, AWS, or Azure) for designing and operating production workloads. Proven track record of delivering large-scale, high-performance, and reliable systems.Expertise in RESTful API design and scaling, including data modeling, error handling, performance optimization, and security best practices. Strong background in distributed systems, Kubernetes, and containerized services. Experience leading architecture and technical direction across multiple teams or product areas. Strong problem-solving skills, with the ability to anticipate and address scalability, reliability, and privacy challenges. Excellent collaboration and communication skills, with success working closely with product, partner engineering, and cross-functional stakeholders. Proven ability to mentor senior engineers and raise technical standards across an organization.NICE TO HAVE: Experience designing real-time, low-latency, large-scale data processing systems. Knowledge of programmatic advertising or other high-throughput transactional platforms. Familiarity with CI/CD pipelines, infrastructure as code (Terraform, Helm), and advanced monitoring/observability tools (e.g. Grafana). Proven ability to introduce architectural patterns that improve developer velocity and system reliability. Experience using AI-assisted development tools to enhance productivity. At OpenX, we have built a team that is uniquely experienced in designing and operating high-scale ad marketplaces, and we are constantly on the lookout for thoughtful, creative executors who are as fascinated as we are about finding new ways to apply a blend of market design, technical innovation, operational excellence, and empathetic partner service to the frontiers of digital advertising. We’re seeking a Principal Engineer with strong platform and cloud expertise to lead large-scale integrations and enhance the scalability and performance of our platform. You’ll join a talented team to design and develop real-time services, working closely with partner engineering and product teams to deliver secure and robust solutions.An ideal candidate is: Open-minded – Welcomes feedback, learns from failure, and adapts quickly to change. Proactive – Takes initiative to identify problems and drive thoughtful, effective solutions. Self-motivated & Organized – Manages priorities independently and follows through with clarity and accountability. We are operating at a scale: 100% Cloud-based (GCP) platform Over 370 billion Ad requests every day Over 120 000 CPU daily Over 140 TB RAM daily Over 50 PB of data per week Over 1200 production deployments a month ,[Lead the architecture and technical vision for platform integrations, ensuring high performance, security, and scalability., Design and build systems that enable partners to connect and operate real-time services efficiently and securely., Work with partner engineering and product teams to plan, build, and launch integrations that meet business and technical goals., Deliver critical platform features from design through implementation, testing, rollout, and adoption., Identify and address technical debt, performance bottlenecks, and scalability risks before they impact customers., Champion architectural patterns and platform capabilities that improve developer velocity and operational reliability., Promote engineering excellence through constructive code reviews, mentoring, and driving improvements in code quality, architecture, and platform best practices.] Requirements: Java, Cloud, Kubernetes, REST API, Distributed computing, Google Cloud Platform, Golang, PostgreSQL, Docker, JVM, Spring, AWS Tools: Jira, Confluence, GitHub, GIT, Cloud Build, Agile, Scrum, Kanban. Additionally: Small teams, International projects, Private healthcare, Lunch card, Multikafeteria, Life & group insurance, Flat structure, Free coffee, Canteen, Bike parking, Shower, Free snacks, Free beverages, Free lunch, Free parking, In-house trainings, Modern office, No dress code.