Senior Software Engineer

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