Job Summary: We are looking for a Senior Fullstack Developer – AI Agents to join our AI team and build production agentic systems that optimize workforce management. Key Highlights: 1. Build production agentic systems with direct impact on users. 2. Design and develop end-to-end agentic applications. 3. Work with cutting-edge technology and real systems in production. Hi! We’re looking for our next star hire as Senior Fullstack Developer – AI Agents. We are Sesame HR, the digital solution that helps HR teams, managers, and companies optimize workforce management processes by centralizing them on a single platform. In this role, you’ll join our AI team, where we’re building production agentic systems processing thousands of daily interactions and delivering direct impact on 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 with Docker and cloud deployments (AWS, GCP, or Azure). * Practical 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 drive to improve both product and existing code. **✨ Bonus points if you also have:** * Strong Python experience for AI application development. * Proficiency in Symfony (PHP) for backend development. * Experience with Vue 3 and/or React for frontend development. * Designed 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 the product, the team, and our approach to applied AI, supported by technical onboarding and mentoring. * In your first months, you’ll develop and evolve key agentic features, working side-by-side with the AI and Product teams. * As you gain context, you’ll begin defining architecture, proposing improvements, and leading technical decisions. * Once fully embedded, 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:** * 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 systems in production, and a team deeply committed to doing things right. **Salary range:** 40.000 - 50.000€ Are you up for the challenge?