Lead, Software Engineer

Senior Software Engineer

A subsidiary of Publicis Groupe, Epsilon is a leading provider of multi-channel marketing services, technologies, and database solutions. At Epsilon, we do more than collect and store data. We help some of the world's biggest brands discover real opportunities inside the data types, delimiters and decimals. We are looking for a highly experienced Senior Software Engineer 7+ years to design, build, and scale robust backend systems using Java and Python in an Agile environment. This role has a strong emphasis on spec-driven AI-assisted development, where engineers leverage clear technical specifications and modern AI coding tools such as Cursor, Claude Code, and Kiro to accelerate development while maintaining high engineering rigor and production quality. Join us and do some truly astounding things.

Responsibilities

• Design, develop, and maintain scalable backend services using Java and Python
• Apply spec-driven AI-assisted development as a core development practice, including:
• Translating detailed functional and technical specifications into high-quality code using AI tools
• AI-assisted code generation, refactoring, and optimization with strong human validation
• Prompt-driven development aligned to explicit design and acceptance criteria
• Intelligent debugging, test generation, and code reviews using tools like Cursor, Claude Code, and Kiro.
• Build and integrate RAG-based solutions and Agentic AI workflows into enterprise systems
• Lead system design and architecture discussions
• Ensure high code quality through reviews, testing, and engineering best practices
• Collaborate with product, data, platform, and cross-functional teams
• Own and resolve complex production issues

Qualifications

• Bachelor's or Master's degree in Computer Science, Engineering, or a related field (or equivalent practical experience)
• 7+ years of hands-on software development experience
• Strong expertise in Java and Python
• Strong backend engineering experience with Java (e.g., Spring or similar frameworks) and production-grade service development
• Experience with common Java build and delivery tooling (e.g., Maven / Gradle) and source control workflows (e.g., Git, pull requests)
• Strong Data Modeling skills and experience with relational and NOSQL databases
• Experienced working in Unix/Linux environments, including automation and scripting
• Mandatory experience with spec-driven AI-assisted development
• Practical, day-to-day usage of AI coding tools such as Cursor, Claude Code, and similar platforms
• Ability to validate, refine, and productionize AI-generated code against explicit specifications
• Mandatory hands-on experience with:
• RAG (Retrieval-Augmented Generation) architectures
• Agentic AI systems (tool-using agents, orchestration, multi-step reasoning workflows)
• Strong fundamentals in:
• Data Structures & Algorithms
• Object-Oriented Programming
• Design Patterns and System Design
• Experience building and operating backend systems in production
• Solid understanding of REST APIs, microservices, and distributed systems
• Proven ability to own problems end-to-end, including driving design, implementation, testing, and production support
• Demonstrated technical leadership (mentoring junior engineers, raising code quality via reviews, and ensuring implementations meet specifications and standards)
• Experience working in Agile / Scrum teams