Senior Software Engineer

Overview About Business Unit: The Product team forms the crux of our powerful platforms and helps connect millions of customers worldwide with the brands that matter most to them. This team of innovative problem solvers develops and builds products that position Epsilon as a differentiator, encouraging an open and balanced marketplace built on respect for individuals, where every brand interaction holds value. Our full-cycle product engineering and data teams chart the future and set new benchmarks for our products, by using industry standard methodologies and sophisticated capabilities in data, machine learning, and artificial intelligence. Driven by a passion for delivering smart end-to-end solutions, this team plays a key role in Epsilon’s success story. About the Role: We are looking for a Senior Software Engineer (Full Stack) to help design and build scalable, high-performance platforms that power data-driven marketing and advertising use cases. This is a high-impact role for an engineer who thrives with ownership, understands system-level thinking, and enjoys working across frontend, backend, and data layers. You will contribute to architecture and implementation, optimize performance and reliability, and collaborate closely with product, design, and platform teams to deliver robust solutions used at scale. In this role, you will also help bring AI-driven capabilities into our ad server platform, including an agentic framework and supporting services that expose platform capabilities to agents through emerging standards such as MCP (Model Context Protocol) and AdCP (Ad Context Protocol). Click here to view how Epsilon transforms marketing with 1 View, 1 Vision and 1 Voice. Responsibilities Design, implement, and operate scalable, high-throughput web applications and services Build and evolve backend services, APIs, and data integrations supporting data-intensive workflows Develop modern, performant user interfaces and internal tools when needed Contribute to an agentic framework for the ad server platform, streaming chat surfaces, generative UI components, tool-use visualizations, and human-in-the-loop flows Build MCP servers/clients and AdCP integrations that expose ad server capabilities to internal and partner agents Collaborate with product and design teams to translate business requirements into technical solutions Optimize performance, troubleshoot production issues, and eliminate bottlenecks across the stack Champion clean code, testing best practices, and CI/CD automation Contribute to system observability, monitoring, and reliability improvements Mentor junior engineers and actively participate in design and code reviews Qualifications Years of experience 5-8 years. Strong experience with frontend frameworks (React, js, Angular) Strong experience with backend development (Java, js, or Python) Hands-on experience with SQL and NoSQL databases (MySQL, PostgreSQL, BigQuery, ) Experience building and consuming RESTful APIs (gRPC is a plus) Exposure to Docker and Kubernetes in production environments Experience working with cloud platforms (AWS, GCP or Azure) Proficiency with Git and CI/CD tools (Jenkins, GitHub Actions) Hands-on experience integrating LLMs (OpenAI, Anthropic, Bedrock, or open-source models) into production applications Familiarity with agent/LLM orchestration frameworks (LangGraph, LlamaIndex, or similar) Exposure to MCP (Model Context Protocol) or comparable tool-use/plugin protocols for agents Experience with prompt engineering and LLM evaluation/observability tooling (LangSmith, LangFuse, Braintrust, or similar) is a plus AdTech experience (ad servers, DSPs, SSPs, programmatic standards) is a bonus Additional Information Epsilon is a global data, technology and services company that powers the marketing and advertising ecosystem. For decades, we’ve provided marketers from the world’s leading brands the data, technology and services they need to engage consumers with 1 View, 1 Vision and 1 Voice. 1 View of their universe of potential buyers. 1 Vision for engaging each individual. And 1 Voice to harmonize engagement across paid, owned and earned channels. Epsilon’s comprehensive portfolio of capabilities across our suite of digital media, messaging and loyalty solutions bridge the divide between marketing and advertising technology. We process 400+ billion consumer actions each day using advanced AI and hold many patents of proprietary technology, including real-time modeling languages and consumer privacy advancements. Thanks to the work of every employee, Epsilon has been consistently recognized as industry-leading by Forrester, Adweek and the MRC. Epsilon is a global company with more than 9,000 employees around the world. Our pillars aren't just words. They're how we show up every day. People centricity: We focus on employee well-being in an environment where colleagues truly care about each other. Collaboration: We work together, support one another, and collectively achieve goals. Growth: There are endless opportunities for growth through learning, development and career advancement. Innovation: We drive progress through cutting-edge solutions and forward-thinking approaches. Flexibility: We’ve created a balance between work and personal life, and we encourage adaptability to solve problems creatively. Our values guide us to create value for our clients, our people and consumers. Act with integrity Work together to win together Innovate with purpose Respect all voices Empower with accountability These pillars and values are our foundation—shaping our culture, guiding our decisions, and uniting us in common purpose. Epsilon is an Equal Opportunity Employer. Epsilon is committed to promoting diversity, inclusion, and equal employment opportunities by using reasonable efforts to attract, recruit, engage and retain qualified individuals of all ethnicities and backgrounds, including, but not limited to, women, people of color, LGBTQ individuals, people with disabilities and any other underrepresented groups, traits or characteristics.

Years of experience 5-8 years. Strong experience with frontend frameworks (React, js, Angular) Strong experience with backend development (Java, js, or Python) Hands-on experience with SQL and NoSQL databases (MySQL, PostgreSQL, BigQuery, ) Experience building and consuming RESTful APIs (gRPC is a plus) Exposure to Docker and Kubernetes in production environments Experience working with cloud platforms (AWS, GCP or Azure) Proficiency with Git and CI/CD tools (Jenkins, GitHub Actions) Hands-on experience integrating LLMs (OpenAI, Anthropic, Bedrock, or open-source models) into production applications Familiarity with agent/LLM orchestration frameworks (LangGraph, LlamaIndex, or similar) Exposure to MCP (Model Context Protocol) or comparable tool-use/plugin protocols for agents Experience with prompt engineering and LLM evaluation/observability tooling (LangSmith, LangFuse, Braintrust, or similar) is a plus AdTech experience (ad servers, DSPs, SSPs, programmatic standards) is a bonus

Design, implement, and operate scalable, high-throughput web applications and services Build and evolve backend services, APIs, and data integrations supporting data-intensive workflows Develop modern, performant user interfaces and internal tools when needed Contribute to an agentic framework for the ad server platform, streaming chat surfaces, generative UI components, tool-use visualizations, and human-in-the-loop flows Build MCP servers/clients and AdCP integrations that expose ad server capabilities to internal and partner agents Collaborate with product and design teams to translate business requirements into technical solutions Optimize performance, troubleshoot production issues, and eliminate bottlenecks across the stack Champion clean code, testing best practices, and CI/CD automation Contribute to system observability, monitoring, and reliability improvements Mentor junior engineers and actively participate in design and code reviews