Senior Software Engineer

Epsilon is building the next generation Retail Media Network (RMN) platform to power onsite advertising at scale, leveraging services from our industry-leading platform that already serves billions of offsite ads across the open web. Our vision is a unified platform for both onsite and offsite ads, delivering low-latency, high-throughput performance across the board. We’re looking for a Senior Software Engineer to join our Core Platform Engineering team, someone with a self-starter mindset who thrives with minimal direction, can quickly grasp business and technical goals, and takes ownership from concept through delivery. This is a high-impact role where you’ll shape the architecture, optimize performance, and ensure our systems are built for scale, reliability, and innovation. You’ll be at the forefront of building a next-generation advertising platform that combines the speed and sophistication of programmatic ad serving with the personalization and commerce power of retail media. Your work will directly shape how millions of users experience advertising across top retailers and brands. What You’ll Achieve

• Design, implement, and maintain high-performance, low-latency services for advertising.
• Collaborate with product, platform, and operations teams to integrate new capabilities into the platform.
• Optimize system performance, fix production issues, and eliminate bottlenecks across the stack.
• Contribute to frontend integrations (SPAs, dashboards, tools) when needed, ensuring seamless workflows for internal and external users.
• Partner with data engineering teams to design and integrate event tracking, analytics, and reporting pipelines.
• Champion code quality, testing standard processes, and CI/CD automation.
• Deliver mission-critical enhancements enabling fast, accurate, and scalable ad delivery.
• Build robust, future-proof services and interfaces that empower rapid feature development.
• Improve system observability, monitoring, and fault tolerance.

• Bachelor’s degree in Computer Science or related field (or equivalent experience).
• 6+ years of experience in backend and/or full stack software development.
• Strong backend expertise in Java, with experience in high-performance, distributed systems.
• Experience with streaming platforms (e.g., Kafka, Kinesis, Pulsar).
• Proficiency with relational databases (SQL) and NoSQL data stores.
• Understanding of low-latency, high-throughput architectures and clean software design principles.
• Experience building SPAs with TypeScript and modern frameworks (Angular, React, or similar).

Why you might stand out from other talent:

• Master’s degree or 10+ years software engineering experience.
• Experience in ad tech, especially ad serving, RTB, or programmatic platforms.
• Familiarity with cloud-native environments (AWS, Kubernetes, Docker).
• Experience with large-scale event tracking, data pipelines.