Senior Fullstack Developer – AI Agents

Description

Job Summary: We are seeking a Senior Fullstack Developer – AI Agents to join our AI team, building production-grade agentic systems that optimize personnel management. Key Highlights: 1. Join an AI team building production-grade agentic systems. 2. Design and develop end-to-end agentic applications for HR. 3. Work with cutting-edge technology and real-world production systems. Hello! We’re looking for our next star hire for the Senior Fullstack Developer – AI Agents role. We are Sesame HR, the digital solution helping HR teams, managers, and companies optimize personnel management processes by centralizing them on a single platform. In this role, you’ll join our AI team, where we’re building production-grade agentic systems processing thousands of daily interactions and directly impacting our users’ experience. What do we expect from you? **Technically, the following are essential:** * 5+ years of software development experience, with focus on complex production systems. * Solid experience developing AI applications beyond prototypes or research. * Designed, built, and deployed autonomous agents in production. * Experience with multi-agent orchestration, state management, memory, and autonomous decision-making. * Practical knowledge of tool use, function calling, and agent integration with APIs and external systems. * Experience implementing RAG pipelines and working with vector databases (Pinecone, Chroma, pgvector…). * Integration of LLM APIs such as OpenAI, Anthropic, or open-source models. * Ability to design scalable and reliable architectures for production AI systems. * Experience working with Docker and cloud deployments (AWS, GCP, or Azure). * Pragmatic mindset: here, we build real products—not academic research. * Ability to understand business problems and translate them into effective technical solutions. * Adaptability to change (yes, we’re a startup). * Constant curiosity and eagerness to improve both the product and existing code. **✨ You’ll stand out even more if you have:** * Strong Python experience for AI application development. * Mastery of Symfony (PHP) for backend development. * Experience with Vue 3 and/or React for frontend development. * Experience designing evaluation frameworks to measure agent reliability and quality. * Familiarity with techniques such as reflection, self-correction, and response verification in agents. * Comfort working with distributed systems and modern architectures. ‍ ‍ What will you do at Sesame? * Design and develop end-to-end agentic applications for HR process automation. * Build multi-agent systems with orchestration, memory, and autonomous decision-making. * Implement RAG pipelines to provide enterprise context to agents. * Create guardrails and human-in-the-loop workflows to ensure reliability and compliance. * Maintain and evolve our backend in Symfony, Python, and NodeJS, and frontends in Vue 3 / React. * Define scalable architectures for production AI systems. * Collaborate closely with product to transform business needs into real agentic solutions. What will your growth path look like within the company? * In your first weeks, you’ll deeply learn our product, team, and applied AI approach through technical onboarding and mentoring. * In your first months, you’ll develop and evolve key agentic features, working hand-in-hand with the AI and product teams. * As you gain context, you’ll begin defining architecture, proposing improvements, and leading technical decisions. * Once fully established, you’ll play a key role in evolving our AI platform, directly influencing the roadmap and technical strategy. ✈️ Every feature is a new adventure **Our current tech stack includes:** * Backend: Symfony (PHP), Python, NodeJS, FastAPI * Frontend: Vue 3, React * AI / ML: LangChain, LangGraph, Mastra, OpenAI, Anthropic * Infra: AWS, Docker, PostgreSQL, Redis * Data: pgvector, embeddings, RAG pipelines You’ll work with cutting-edge technology, real-world production systems, and a team highly motivated to do things right. **Salary range:** €40,000 – €50,000 Are you up for the challenge?