Senior Machine Learning Scientist

Senior Machine Learning Scientist

Zendesk

Krakow, Lisbon or Remote

As a Senior Machine Learning Scientist, you will drive development, evaluation, and deployment of novel ML/AI models to power intelligent automation and customer service solutions at scale. You will collaborate closely with engineers, product managers, and cross-functional teams to translate research into solutions directly impacting millions of support interactions.

What you get to do every day:

• Research, prototype, and develop state-of-the-art NLP/ML models for use cases such as intent detection, auto-assist, chatbots and intelligent agent routing.
• Design and execute rigorous experiments and evaluations (offline/online, A/B) to improve model accuracy and robustness.
• Work closely with ML Engineers to productionize ML solutions - including data pipelines, scalable model serving, and monitoring.
• Analyze large, multi-lingual customer interaction datasets to uncover insights and power new solutions.
• Participate in technical reviews and share knowledge of underlying ML methodologies and best practices.
• Present your work to a multi-disciplinary, global audience.
• Stay up to date with recent literature in Machine Learning and Natural Language Processing (NLP) and share knowledge internally.
• Champion initiatives to improve the quality and robustness of Zendesk AI capabilities.
• Mentor junior scientists and help grow the ML research culture.

Key challenges/use cases:

• How do we enrich customer service conversations with accurate language detection, intent recognition, and real-time sentiment analysis, to enable proactive customer engagement and optimal routing?
• How can we automate all customer service interactions as much as possible, from process automation to agent assistance and chatbots with a knowledge base?
• How do we optimize routing at scale - matching tickets or chats to the most appropriate agent/team in real-time across multiple languages and regions?
• How do we automate large-scale A/B testing and model evaluation (online and offline) to continually iterate and improve ML-driven triage and agent-assist tools?
• What novel approaches or architectures (e.g., retrieval-augmented generation, few-shot/fine-tuning strategies) can extend our conversational AI platforms to unlock new customer support use cases and modalities?
• How do we efficiently operationalize, monitor, and update large-scale (LLM/ML) models in dynamic, high-throughput production settings, ensuring model health, drift detection, and continuous learning?
• How do we combine signals from conversation context, customer history, and external data to improve prediction and decision accuracy across our ML services?
• What are the emerging advancements in ML/AI research (e.g., large language models, efficient adaptation, re-ranking, retrieval, or explainable AI) that should be incorporated into Zendesk’s customer experience ecosystem?
• How can we bridge the gap between cutting-edge research and impactful product features, rapidly validating ideas in production and quantifying their real-world business value?
• And many more!

What you bring to the role:

• MSc degree (PhD preferred) in computer science, electrical engineering, math, or related areas.
• Deep knowledge of ML theory, algorithms, and modern NLP/LLM techniques.
• Demonstrated ability to conduct independent research and deliver production-grade ML solutions.
• Strong coding skills in Python; experience with ML frameworks (preferably PyTorch).
• Experience with large-scale experimentation (e.g., A/B testing), data analysis, and performance tracking.
• Strong collaboration and communication abilities.
• Be pragmatic and results oriented.