**Job Title: AI Engineer
Reports to:** Head of AI
Company: Replenit (www.replen.it)
Location: Warsaw / Remote
The Mission
Replenit is moving the e-commerce world from "if-this-then-that" flows to autonomous decision-making. We’ve built an AI Decision Engine that acts as the "brain" for global brands, predicting when a customer is about to run out of a product or is ready for an upsell/cross-sell/churn. As an AI Engineer here, you won't be tucked away in a lab; you will be building the core agents that drive millions of dollars in incremental revenue for our clients.
The Role
Reporting directly to the Head of AI, you will be responsible for the "intelligence" layer of the platform. You will design, build, and optimize the models and agentic workflows that decide what message to send, when to send it, and to whom. You’ll be turning raw behavioral data into autonomous commerce actions.
Key Responsibilities
- Agent Architecture: Develop and refine our "Theory of Mind" agents (Replenishment, Cross-sell, Churn Prevention) using a mix of LLMs, predictive modeling, and reinforcement learning.
- Production-Grade AI: Move beyond the "wrapper." You will build robust, scalable pipelines that process high-velocity e-commerce data (orders, clicks, views) into actionable predictions.
- Optimization & Reasoning: Fine-tune how our agents "reason" through multi-variable constraints—balancing brand guidelines, inventory levels, and customer sentiment.
- Rapid Prototyping: Work with the CPO to ship "0 to 1" AI features. You’ll build MVPs of new agents, test their uplift, and then harden them for enterprise-grade deployment.
- Data Strategy: Collaborate with the engineering team to optimize our vector databases and data ingestion from sources like Snowflake, BigQuery, and Shopify.
Technical Stack & Requirements
- The Essentials: 3+ years of experience in AI/Machine Learning Engineering. You are a pro with Python and have deep experience with PyTorch, TensorFlow, or Scikit-learn.
- Modern AI Patterns: Hands-on experience with LLM orchestration (LangChain, LlamaIndex), Prompt Engineering, and RAG architectures.
- Data Mastery: Strong SQL skills and experience working with large-scale behavioral datasets. You understand how to handle noisy e-commerce data.
- Infrastructure: Experience deploying models in cloud environments (AWS/GCP) and an understanding of MLOps (monitoring model drift, latency, and accuracy in production).
- Startup DNA: You ship fast. You understand that a "perfect" model that never launches is useless. You prioritize business impact over academic purity.
Bonus Points
- Experience building autonomous agents or multi-agent systems.
- Background in E-commerce, MarTech, or AdTech.
- Knowledge of causal inference (distinguishing between "this customer was going to buy anyway" vs. "the AI drove this purchase").
Why Replenit?
- No Red Tape: You report to the Head of AI, an academic with a fantastic background and experience. If you have a better way to build a model, you build it.
- Real-World Impact: Your code will trigger millions of interactions for some of the world’s biggest brands.
- Elite Team: Join a founding team that has already scaled global tech companies and is now disrupting the retention space.
Job Type: Full-time
Pay: 9,071.27zł - 15,484.98zł per month
Work Location: Remote