AI/ML Engineer

Rebtel is a profitable company founded in 2006, with 73 employees across 31 countries serving 1 million users, providing data-free international calling and mobile top-ups for diaspora communities, based in Stockholm with global operations.

Rebtel is hiring an AI/ML Engineer in Stockholm to build classical ML and LLM-powered systems for the product, reporting to the Head of Data and partnering with another ML/AI engineer.

The role encompasses two complementary tracks:

Classical ML Track:

• Build risk and fraud models for payments, top-ups, and account behavior
• Develop churn prediction and retention models for the 1M+ user base
• Handle forecasting, pricing, and segmentation
• Own models end-to-end: scoping, building, deployment, monitoring, retraining

LLM/AI Agents Track:

• Develop customer support agents and automations
• Build RAG pipelines, prompt orchestration, and tool-use systems
• Build evaluation harnesses
• Evaluate and guide AI implementation across the company
• Move LLM capabilities into the product as user-facing features

The role progresses from internal automation (such as customer support agents) to shipping AI features directly to users, helping guide the company on where AI actually creates leverage and turning good ideas into shipped systems.

Required experience and qualifications:

• 4+ years of hands-on ML engineering in Python, with real production ownership
• Strong classical ML fundamentals and a production mindset
• Experience building RAG systems or LLM-backed products
• Hands-on experience with LLM frameworks: LangChain, LangGraph, LlamaIndex
• RAG systems and agentic workflow experience
• Vector databases, embeddings, and prompt evaluation expertise
• MLOps tooling (MLflow, Airflow, Kubernetes, feature stores)
• Cloud experience (AWS/GCP/Azure) and containerization
• Strong English communication and business-to-ML translation skills

Benefits: Pension plan and occupational insurance, health checkups, influenza shots, private medical insurance, dental insurance, 5,000 SEK wellness allowance, gym membership discounts, bonus program, extra parental pay, 30 days annual vacation, relocation support.