Data Scientist / AI Engineer

ABOUT LEMLIST lemlist is the AI-powered sales engagement platform helping sales teams build pipeline smarter, not harder. Bootstrapped from day one, we’ve grown from 0 to $50M+ ARR in 8 years without raising a single dollar. Today, 40,000+ sales teams use lemlist to book more meetings and close more deals. We’re building the next generation of outbound: AI-first, multi-channel, highly personalized, and deeply integrated into the way modern sales teams work. And we’re just getting started. We’re looking for a Data Scientist / AI Engineer to join our team. You'll be responsible for identifying and shipping AI use cases that have a direct impact on the product and the business, working closely with Product and Engineering teams. YOUR MAIN MISSION WILL BE: - Identify where AI can create leverage across the product, propose concrete use cases, and take ownership from problem framing to production. - Design, develop, and maintain LLM-based systems: prompt engineering, orchestration, retrieval pipelines, evaluation frameworks, observability… - Deploy and operate AI models and infrastructure, including GPU server management and model serving. - Design, train, evaluate, and maintain Machine Learning models in production. - Support business and product teams with data-driven insights. KEY RESULTS Within 3 months, you will have/be: - Successfully onboarded and integrated into the team. - Have a clear understanding of the product, data, and existing AI systems. - Audited existing LLM systems and ML models, identified quick wins and gaps. - Shipped a first AI use case end-to-end in production. - Set up or improved evaluation frameworks for at least one existing LLM system. Within 12 months, you will have: - Shipped several meaningful AI use cases that have a measurable impact on the product. - Built a solid evaluation and observability layer across multiple LLM systems in production. - Improved significantly the AI culture within lemlist. - Supported the C-level (CEO, CPO, CMO, Head of Sales…) for strategic decisions. WHAT’S IN IT FOR YOU? - Work in a profitable, bootstrapped, and high-growth company that doesn’t rely on external funding to live. - Work on high-impact projects with highly skilled data profiles composed of a Senior Analytics Eng, a Senior Data Engineer and a Data Analyst that directly drive business decisions - Collaborate directly with the C-suite on strategic topics - Work with a team obsessed with speed, growth, and impact. PREFERRED EXPERIENCE Must have: - 4+ years in a Data Science or AI Engineering role, ideally in a fast-moving environment. - Advanced Python and SQL skills. - Strong hands-on experience building and operating LLM-based systems: model APIs, agentic pipelines, RAGs, evaluation, and observability. - Proficiency with agent-based frameworks such as LangChain. - Hands-on experience with deep learning libraries (PyTorch, Transformers) and embeddings (SentenceTransformers). - Experience deploying and managing models on cloud infrastructure (ideally GCP suite). - Familiarity with CI/CD tools (Docker, Jenkins or equivalent). - Strong interest in getting things into production. - Strong analytical and problem-solving mindset. - Fast learner, high ownership, structure, and execution speed. - Fluent in French and English. - Paris based (Paris office / remote). Nice to have: - Experience with workflow orchestration tools (Airflow or equivalent). - Experience managing GPU servers for model training and serving. - You have a first experience in B2B SaaS startup - Knowledge of general IT good practices - maintainable and commented code, GitHub… ADDITIONAL INFORMATION - Competitive salary and company bonus (up to 18K€ per year depending on company’s performance) - 38 days of holidays/year - Alan Blue: Comprehensive 100% premium medical coverage for you and your family - Swile Meal Tickets: Enjoy daily meal tickets to fuel productivity - Navigo Card: Seamless commuting with a 100% covered Navigo card - Gear: Get the laptop, tools, and equipment you need for your job - Team building: We all meet once per year at really cool places around the world (check our video here https://www.youtube.com/watch?v=nwUEuQXa4Jw) RECRUITMENT PROCESS 1. 1st call with Victoire our TAM & Ahmed our AI Engineer 2. Live technical interview with Ahmed & Eliott - Lead data 3. Interview with Charles, CEO 4. Reference Check & Offer