Senior AI Backend Engineer - France and Poland

The AI Agents Platform Team is at the heart of LumApps' most ambitious product bets. We design, build, and evolve the backend systems that power AI-driven experiences across the platform - from conversational agents and agentic workflows to RAG pipelines, multi-agent orchestration, and real-time streaming infrastructure. Our backend scope includes:

• Agent Engine: the core orchestration layer powering multi-agent systems using Google ADK and AWS Strands, with LLM routing, tool execution, stateful session management, and real-time streaming via the AG-UI protocol and Server-Sent Events
• RAG & Knowledge Retrieval: retrieval-augmented generation pipelines that connect agents to LumApps content, with source attribution, reranking, and sub-agent exploration
• Agent Studio Backend: the data layer and API surface for creating, configuring, and governing AI agents at scale - tools, permissions, feature flags, YAML-driven agent definitions, and multi-tenant architecture
• Observability: tracing and metrics via Langfuse and OpenTelemetry to monitor LLM calls, tool invocations, and agent behavior in production

Missions

As a Software Engineer (Backend), you will own meaningful end-to-end contributions on the most technically complex parts of our stack. You will work alongside senior engineers, backend specialists, and AI researchers, with direct exposure to the full lifecycle of AI-powered features - from database schema to production deployment. Missions

• Technical Ownership & Delivery Independently scope and implement solutions for your team's projects. Make well-reasoned design decisions, identify tradeoffs and risks, and select the appropriate level of abstraction. Handle open-ended problems and ambiguity well, and ship frequently to mitigate risk. Estimate rigorously based on iterative learning, and hold yourself accountable end-to-end - through planning, deployment, maintenance, and monitoring.
• Cross-Functional Collaboration Communicate technical issues and decisions clearly and proactively to a cross-functional audience - including product, design, and other engineering teams. Share bad news quickly. Engage in productive dialog even when there are conflicting views, and ensure critical systems are documented.
• Quality & Security Write meaningful code reviews that raise the bar for the whole team. Proactively identify and help resolve problems that impact your team. Design with security in mind and seek reviews on security-sensitive areas. Use KPIs and a strong product understanding to inform decisions and measure impact.
• Growth & Team Contribution Mentor junior engineers on technical subjects. Lead and coach within your team where trusted. Elevate testing practices. Broaden your impact by considering the effects of your work on adjacent teams, and help drive hiring by reviewing technical tests and conducting technical interviews.

Do you have experience in YAML?, * A Proficient Python Backend Engineer: You have 3-5 years of professional backend experience, with solid Python skills and a strong grasp of Clean Architecture and SOLID principles. You are comfortable navigating a large monorepo and confident writing well-tested, maintainable code at scale.

• An AI & Agent Systems Builder: You are excited about building at the frontier of AI. You have hands-on experience - or a strong curiosity - with agent orchestration frameworks like Google ADK or AWS Strands, RAG architectures, and LLM providers such as Google Gemini running on Vertex AI and Mistral. You understand how to build stateful multi-agent systems and are comfortable with real-time streaming patterns (SSE, AG-UI protocol).

• Comfortable with the Full Backend Stack: You understand the systems you touch - Flask for HTTP APIs, SQLAlchemy + Alembic for data modeling and migrations, Redis for caching and session management, PostgreSQL with multi-tenant schema partitioning, Pub/Sub for event-driven flows, and GCS for file storage. You know how to deploy to GCP and understand production monitoring via OpenTelemetry and Langfuse.

• A Quality Champion: You write tests with confidence - unit tests that cover business logic, component tests that validate the HTTP layer against a real database. You know the difference between testing for coverage and testing for confidence, and you actively raise the bar for the team.

• A Technical Communicator: You can express complicated issues simply. You write clear design documents, participate actively in design reviews, and flag risks early. You communicate in English fluently across engineering, product, and stakeholder audiences.

• A Security-Conscious Engineer: You consider security implications when designing systems - particularly around multi-tenancy, API access, and LLM input/output boundaries. You proactively seek review on security-sensitive changes.

• A Collaborative Teammate: You give direct, constructive feedback in code reviews and mentoring. You seek to understand other points of view and contribute to a team culture grounded in psychological safety and technical excellence.

LumApps is now more than just an Employee Experience Platform - it is an AI-powered Employee Hub that supports companies in their digital transformation of communication, collaboration, and engagement with their customers, partners, and above all their employees. Our platform is a proven leader in this dynamic market with a truly unique vision and product. It has been deployed by Fortune 500 clients around the world and is delivering meaningful business benefits. LumApps is identified as a leader in Gartner's Magic Quadrant for Intranet Packaged Solutions as well as in Intranets Forrester Wave, and regularly selected for the French Tech Next40/120 program. In 2025, LumApps strengthened its leadership position by partnering with Beekeeper, a pioneer in frontline employee experience solutions. This strategic collaboration expands our reach and impact across all types of workers - from HQ to the frontline. Our mission: To make people feel that they belong and have a purpose. To create an environment where all employees are engaged and work together towards the same goal. Over 700 leading companies trust our solution to: Improve the productivity of their teams with our AI-powered Collaborative Experience Platform integrated with both Google and Microsoft collaborative suites, Transform employees into real ambassadors of their company, Make employees more efficient and better connected to their peers and relevant information, regardless of their location, with the tools and information they need at their fingertips, Help companies reduce turnover, accelerate employee onboarding, better collaborate and share knowledge, and even improve their customer experiences. With a team of over 600 Lumies spread across 11 offices (Lyon, Paris, Lille, Sophia Antipolis, London, Barcelona, Hamburg, Austin, Tokyo, Zurich, Krakow), we support large enterprises all around the world. Over the past year, we have been driving an ambitious phase in our journey under the impulse of our new shareholder Bridgepoint, aimed at propelling us to become the clear leader in our market and shine worldwide in our industry. We are looking for individuals who are excited to actively participate in this transformation.