Senior Data Scientist (macOS AI assistant)

MacPaw is a software company that develops and distributes software for macOS and iOS. Today, we have 20 million active users across all our products.
At MacPaw, we believe humans and technology can reach their greatest potential together.
MacPaw is proud to be Ukrainian. The support and development of Ukraine are significant parts of the company's culture. MacPaw gathers open-minded people who support each other and aspire to change the world around us.
Imagine working on an AI-powered macOS assistant that feels truly intuitive, smart, and seamlessly integrated into users' daily workflows. At MacPaw, we're pushing LLM-powered agents to the next level, and we need a Senior Data Scientist to help us get there.
In this role, you won't just build models-you'll shape the next generation of on-device AI, tuning LLMs to achieve SOTA performance, RAG pipelines, and intelligent agents for real-world applications. You'll work with top Engineers and Scientists to bring cutting-edge NLP and ML capabilities directly to macOS users.
If you're passionate about LLMs, AI agents, and making AI more accessible and powerful, this is your chance to be at the forefront of a game-changing innovation.
P.S. Here , you can learn more about our macOS AI assistant.
In this role, you will:

• Fine-tune LLMs
• Develop and fine-tune LLM-based agents for local task execution
• Design and build advanced RAG (Retrieval-Augmented Generation) pipelines for improved information retrieval
• Lead general deep-learning training and experimental initiatives. Cooperate with and mentor students from top Ukrainian universities
• Apply classical NLP techniques (e.g., NER, POS tagging)
• Set up a testing framework to evaluate agent performance, measure key metrics, and identify optimization opportunities
• Supervise macOS Engineers to integrate models on device

Skills you'll need to bring:

• Advanced experience in NLP and LLMs
• Proven ability to train custom NLP models and fine-tune pre-trained LLMs
• Strong background in Transformer architectures and their applications
• Proficiency in classical ML tasks (classification, regression, clustering)
• Experience with Python and NLP/ML frameworks (PyTorch, spaCy, NLTK, SciPy)
• Hands-on experience building LLM agents (RAG, ReAct, Plan&Execute, multi-agent systems)
• Good expertise in creating competitive advantage through LLM fine-tuning and RAG optimization
• Familiarity with LLM agent frameworks (LangChain, LangGraph, Vector Databases)
• Experience implementing metrics frameworks that align AI performance with business outcomes
• At least an Intermediate level of English

As a plus:

• Knowledge of running and optimizing open-source LLMs
• Background in conversational AI and dialog systems
• Familiarity with iOS/macOS ML frameworks for local deployment
• Experience with edge deployment of ML models
• Expertise with LangFuse or similar observability tools

What We Offer

• We are a Ukrainian company, and we stand with Ukraine against the russian aggression
  
  • We maintain workplaces for the mobilized Macpawians and provide financial support to colleagues or their families affected by the war. Here , you can also read about the MacPaw Foundation, which intends to help save the lives of Ukrainian defenders and provide relief to as many civilians as possible.
• We are committed to our veterans
  
  • Our Veteran Career and Empowerment Program is designed to ensure our veterans and active military personnel receive the recognition, support, and opportunities they deserve.
• Hybrid work model
  
  • Whether to work remotely or at the hub is entirely up to you. If you decide to mix it, our Kyiv office, which works as a coworking space, is open around the clock. The office is supplied with UPS and Starlink for an uninterrupted work process.
• Your health always comes first
  
  • We guarantee medical insurance starting on your first working month. For those abroad, you can receive a yearly Medical insurance allowance as compensation for managing your medical expenses.
• Flexible working hours
  
  • You can choose a schedule that is comfortable for you. No one here tracks your clock in/out because MacPaw is built on trust and cooperation.
• Space to grow both professionally and personally
  
  • Education opportunities to grow both hard and soft skills, annual development reviews, and internal community.
• Teams we are proud of
  
  • We build honest, transparent, and reliable relationships within teams. Every Macpawian can improve processes and implement their ideas. We encourage open and constructive feedback and provide training for Macpawians on giving and receiving feedback.
• Office designed for people (and pets)
  
  • Our office has it all: a spacious workplace with enough room for sitting up, lying down, and running around; a gym for recreation; cozy kitchens; a sleeping/meditation room; and a terrace with a view where we throw summer parties. Also, we have two cats living in the office, and you are welcome to bring your pets to the office (we have separate floors for cats and dogs).
• Time-off policy that covers life's needs
  
  • Convenient personal time-off policy to help you take care of essential matters in your personal life, and parental leaves. On top of all that, sabbaticals are open after 5 years of being with MacPaw.
• Join social initiatives with MacPawCares
  
  • MacPaw participates in numerous humanitarian aid and charity projects across many fields, and you are welcome to jump in to make the world a better place.
• We're an equal-opportunity employer. Here is a safe place for applicants of all backgrounds
  
  • We are hiring talented humans. Meaning with all our variety of backgrounds and identities, including service members and veterans, women, members of the LGBTQIA+ community, individuals with disabilities, and other often underrepresented groups. MacPaw does not discriminate on the basis of race, color, religion, sex, sexual orientation, gender identity, national origin, veteran or disability status.
  • Some benefits are under development, and new adjustments are possible.