Senior Data Scientist / AI Consultant | Mercer
On behalf of Mercer, GT is seeking a Senior Data Scientist / AI Consultant to partner with multiple teams across the client's organization — transforming fragmented data into actionable insights, and delivering production-ready, LLM-powered solutions that drive Mercer’s AI strategy.
Contract Duration: 6 months (with possible extension until the end of 2026)
About the Client Mercer is a global consulting leader in advancing health, wealth, and career outcomes for organizations and individuals. Headquartered in New York City, Mercer operates in over 130 countries with more than 25,000 employees and 180+ office locations worldwide. As part of Marsh McLennan, Mercer provides data-driven insights and tailored solutions in areas such as HR transformation, compensation and benefits, workforce analytics, and employee experience. The company fosters a collaborative, inclusive, and purpose-driven culture that values innovation, integrity, and impact.
About the Role: We’re looking for a Senior Data Scientist / AI Engineer with hands-on experience building and deploying LLM-powered solutions. In this role, you will work closely with Mercer’s internal teams to design LLM classification workflows, develop AI agents, and support the company’s broader AI strategy for 2026.
This role suits someone who thrives in dynamic, exploratory environments where speed, curiosity, and strong engineering fundamentals matter more than heavy MLOps specialization. You will prototype quickly, refine iteratively, and contribute to production-grade implementations as solutions evolve. You will shape and improve LLM applications, define evaluation metrics, and contribute to lightweight production deployments as these solutions mature.
Responsibilities LLM & Agent Workflow Development
- Build and refine LLM-based classification, retrieval, and automation workflows.
- Develop AI agents using frameworks such as LangChain or Mastra AI.
- Prototype rapidly, iterate frequently, and adapt to evolving stacks.
- Design, test, and optimize prompts for reliability and accuracy.
- Define evaluation metrics and data quality standards for LLM workflows.
- Implement validation frameworks and structured evaluation methods.
- Integrate LLM/ML components into internal applications and services.
- Deploy solutions via APIs, cloud endpoints, or lightweight microservices.
- Ensure maintainability, observability, and alignment with stakeholder needs.
- Develop Python code within a shared, production-like codebase (Git).
- Query, structure, and manipulate data using SQL.
- Collaborate on systems involving TypeScript/JavaScript (e.g., Mastra AI).
- Use Databricks for data processing, experimentation, and workflow orchestration.
- Partner with product, engineering, and analytics teams to understand requirements.
- Translate business problems into actionable LLM/AI solutions.
- Communicate effectively with both technical and non-technical stakeholders.
- Contract Duration: 6 months (with possible extension until the end of 2026)
- Remote work options available in Europe and Ukraine.
Essential Skills & Experience
- Strong Python engineering skills in production-like environments.
- Hands-on experience building LLM applications end-to-end (OpenAI, HF, LangChain, Mastra AI, etc.).
- Experience developing AI agents and prompt engineering.
- Experience integrating ML/LLM workflows into applications (API, endpoints, microservices).
- Familiarity with SQL and working with modern data platforms (Databricks).
- Comfortable working with evolving tech stacks and iterative prototypes.
- Ability to define, measure, and improve LLM/agent performance metrics.
- Experience working in agile, fast-paced, or startup-style environments.
Nice-to-Have
- Experience with graph databases (e.g., Neo4j).
- Experience with TypeScript/JavaScript for AI workflows.
- Background in building classification systems or automation pipelines.
- Exposure to cloud ML services (Azure ML, Bedrock, Vertex AI).