Lead Software Engineer (Fullstack, AI LLM)

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. Why are we looking for you ?At Epsilon, we run on our people’s ideas. It’s how we solve problems and exceed expectations. Our team is now growing, and we are on the lookout for dedicated individuals who always set the standard by constantly challenging themselves and are experts in building customized solutions in the digital marketing space. So, are you someone who wants to work with pioneering technology and enable marketers to create data-driven, omnichannel consumer experiences through data platforms? Then you could be exactly who we are looking for. Apply today and be part of a creative, innovative, and experienced team that’s not afraid to push boundaries or take risks . What will you enjoy in this rol e?As a Lead Software Engineer on the Agentic Platform team, you will contribute to design, delivery, technical strategy, and execution for critically important agent platform systems. Depending on level, you will implement well-scoped features, own end-to-end delivery, lead epics and mentor engineers, or define platform-wide architecture and engineering standards. You will help ensure the Agentic Platform scales securely and reliably to support sustained business growth across Epsilon product lines including loyalty, customer data, messaging, digital media, and enterprise AI capabilitie s.Click here to view how Epsilon transforms marketing with 1 View, 1 Vision and 1 Voic e. Responsibilit iesBuild and deliver large-scale cloud-native agent platform capabilities primarily on AWS, leveraging REST APIs, WebSockets, Server-Sent Events (SSE), microservices, and event-driven architectures to create highly scalable and resilient syste ms.Work hands-on across the technology stack — including Python, Django, TypeScript, React, FastAPI, Celery, PostgreSQL, Redis, OpenSearch, AWS Bedrock, Strands Agent SDK, MCP, Terraform, and Docker — to solve complex engineering challenges and maintain platform excellen ce.Design, develop, and operate agent runtime services including spec compilation, pre-flight authorization, skills seeding, MCP tool orchestration, streaming responses, and run package recordi ng.Build and enhance agent builder and product UIs (Agent Cloud, Core Agent, responsive web) and shared frontend libraries using React 19, shadcn/ui, TanStack Query, and type-safe OpenAPI client generati on.Implement MCP catalog, gateway, and federation capabilities; integrate domain MCP servers for loyalty, customer CDP, messaging, digital media, and related enterprise syste ms.Drive performance optimization, scalability, reliability, security, tenant isolation, governance, and cost efficiency across agent execution and platform servic es.Collaborate closely with global engineering, product management, architecture, AI/ML, and business partners to align technical solutions with strategic business objectiv es.Own the end-to-end software development lifecycle, including requirements gathering, solution design, development, deployment, observability, and documentati on.Contribute to observability and quality through OpenTelemetry instrumentation, Grafana/Phoenix tracing, pytest/Vitest/Playwright testing, and CI/CD pipelin es.At Lead and Staff levels: mentor engineers, lead technical design reviews, set engineering standards, and drive cross-team initiatives for runtime performance, MCP federation, orchestration, and multi-tenant sca le.Bachelor’s or master’s degree in computer science, IT, or related fie ld.8–11 years of experience in software engineering, including 8–10 years in technical ownership and delivery leadership rol es.Proven ability to design and deliver scalable, distributed systems across backend, frontend, and runtime laye rs.Strong leadership skills with experience mentoring engineers, leading epics, and driving cross-service executi on.Hands-on expertise in Python and Django (DRF/Ninja) for building production-grade APIs, data models, and async workloads (Celer y).Strong experience with TypeScript and React ecosystems (React 19, Vite, monorepos) for modern web application developme nt.Solid experience in REST APIs, microservices, containerization (Docker/ECS Fargate), and cloud-native architectur es.Proficiency in PostgreSQL, Redis, and search/indexing systems (OpenSearch); exposure to document/graph databases is a pl us.Deep experience with AWS services such as ECS Fargate, RDS, S3, SQS, ALB, IAM, CloudFront, and Bedro ck.Strong understanding of asynchronous systems, messaging, and real-time communication (SSE/WebSocket s).Experience with authentication and authorization (Okta/OIDC, JWT) in multi-tenant SaaS environmen ts.Working knowledge of DevOps and IaC practices (Terraform/AWS CDK), CI/CD pipelines, and testing framewor ks.Exposure to Generative AI technologies (LLMs, RAG, agent-based systems) with hands-on experience preferr ed. Nice to ha ve: Experience with Strands Agent SDK, AWS Bedrock AgentCore, LiteLLM, or comparable agent runtime framewo rks.Experience building MCP servers or tool-calling integrations using FastMCP or similar framewo rks.Experience with agent evaluation (DeepEval, Guardrails AI), LLM observability (Arize Phoenix, Langfuse, OpenTelemetry), and token meter ing.Experience with React Flow (xyflow) for workflow visualization, CodeMirror for in-browser editors, and declarative UI / SSE event stream ing.Experience with Expo / React Native for mobile applicati ons.Experience with A2A (Agent-to-Agent) protocol, cross-account AWS agent execution, and Step Functions / EventBridge orchestrat ion.Working knowledge of Neo4j, Trino, Databricks, or Vertex AI RAG integrati ons.Experience building platforms in privacy-safe, Customer Data Platform (CDP), or Marketing Technology environme nts.Experience with GoCD, Husky pre-commit hooks, Orval OpenAPI code generation, and monorepo development workfl ows. Specialization Tr acks:Platform Backend — Django apps, APIs, Celery, PostgreSQL, tenant isolation, publishing workf lows.Agent Runtime / AI — Strands SDK, Bedrock, MCP, RAG, evaluation, streaming, performance optimiza tion.Frontend / UX — React apps, shadcn/ui, workflow editors, SSE streaming, type-safe API cli ents.Mobile — Expo / React Native companion applica tion.Platform / Infra — Terraform, ECS, observability, CI/CD, cross-account AWS.