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Lead Data Scientist (AI)

AT Exadel
Exadel

Lead Data Scientist (AI)

Sofia, Bulgaria

We are seeking a highly skilled and proactive AI Tech Lead to join our innovative team and spearhead the development of production-level AI agents. The ideal candidate brings a blend of deep technical expertise, hands-on development experience, and proven leadership capabilities in managing cross-functional AI/ML or Data Science teams. You’ll play a key role in architecting intelligent systems, guiding engineers, and pushing the boundaries of applied LLM technologies.

Work at Exadel - Who We Are 

We don’t just follow trends - we help define them. For 25+ years, Exadel has transformed global enterprises. Now, we’re leading the charge in AI-driven solutions that scale with impact. And it’s our people who make it happen - driven, collaborative, and always learning.

About Our Customer

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America’s un-carrier delivers an advanced 4G LTE and transformative nationwide 5G network offering reliable connectivity. The brand operates in parts of Europe, but the U.S. is its largest market. The un-carrier’s customers benefit from its unmatched combination of value and quality and unrivaled drive for disruption, creating competition and innovation in wireless and beyond.

Requirements

  • Background in building and deploying AI agents or intelligent systems at a production level
  • Programming foundation with Object-Oriented Programming (OOP) and API development experience
  • Hands-on leadership of a team of 3–4 DS/SE professionals on AI/ML projects – a must
  • Proficiency in working with at least two different LLMs (e.g., OpenAI, Claude, Mistral, LLaMA, etc.)
  • Familiarity with LangChain and/or LangGraph frameworks
  • Ability to clearly articulate how to break down unfamiliar or abstract problems into manageable development tasks
  • High-level understanding of transformer architectures and their mathematical principles
  • Experience writing clear, user-friendly, and maintainable technical documentation
  • Working hours: till 7-8 pm CET

Nice to Have

  • Background in data science, MLOps, or AI infrastructure
  • Familiarity with prompt engineering, RAG pipelines, or agent-based system design
  • Experience working in a fast-paced startup or product-led environment

English level

Upper-Intermediate+

Responsibilities

  • Lead the design, development, and deployment of production-grade AI agents in collaboration with a multidisciplinary team
  • Break down complex problems into actionable engineering steps and guide the team through delivery
  • Own and manage the full API lifecycle — from design and documentation to integration and maintenance
  • Leverage transformer-based models with a high-level mathematical understanding to build scalable AI solutions
  • Drive code quality, maintain comprehensive documentation, and support reproducibility and model transparency
  • Integrate and experiment with multiple LLMs (Large Language Models) to assess and improve system performance
  • Apply frameworks such as LangChain and LangGraph to build modular AI applications
  • Collaborate with stakeholders to translate business needs into technical solutions
  • Mentor and manage a small team (3-4 Data Scientists/Software Engineers), ensuring alignment and high performance
Client-provided location(s): Sofia, Bulgaria; Hungary; Lithuania; Poland
Job ID: 5497518004
Employment Type: Other