Upwork ($UPWK) is the world’s work marketplace. We serve everyone from one-person startups to large, Fortune 100 enterprises with a powerful, trust-driven platform that enables companies and talent to work together in new ways that unlock their potential.

Last year, more than $3.8 billion of work was done through Upwork by skilled professionals who are gaining more control by finding work they are passionate about and innovating their careers.

The Algorithms and Research Team within the ML & AI organization is responsible for building the foundational models that support all vertical teams, including Search & Recommendations and Upwork’s latest initiative, developing Uma, our AI assistant.

As a Lead Machine Learning Engineer/Scientist, you will play a crucial role in developing and maintaining discriminative and generative AI models. You will design, train/finetune, and evaluate information retrieval systems capable of handling both structured and unstructured databases. Leveraging historical context and diverse data, you will create innovative models to drive significant business impact.

Responsibilities:

• Design and develop retrieval augmentation methods for structured, unstructured, and relational databases.

• Develop and utilize knowledge graphs for information retrieval. Orchestrate information retrieval using knowledge graphs in the loop.

• Investigate model explainability and work with trust and safety teams to enhance reliability and reduce hallucination in Gen-AI models.

• Collaborate cross-functionally with machine learning engineers to take models from research to production.

• Stay current with the latest advancements in Gen-AI and integrate relevant innovations into our systems.

• Mentor junior engineers, conduct code reviews, and enforce engineering best practices. Deliver high-quality solutions that improve overall efficiency.

What it takes to catch our eye:

• Proven experience in designing and developing information retrieval or RAG systems.

• Expertise in vector and graph databases.

• Expertise in Graph Neural Networks (GNNs) and related concepts.

• Familiarity with knowledge graphs and ontology engineering.

• Familiarity with search and recommendations in two-sided marketplaces.

• Passion for developing autonomous agentic systems using LLMs.

• Strong publication record in top-tier conferences like NeurIPS, CVPR, ICML, ICLR, etc. 

Come change how the world works.

At Upwork, you’ll shape talent solutions for how the world works today. We are a remote-first organization working together to create exciting remote work opportunities for a global community of professionals. While we have physical offices in San Francisco and Chicago, currently we also hire full-time employees in 19 states in the United States. 

At the core of our vibrant culture are shared values that form the foundation of our organization. These values revolve around trust, risk-taking, customer focus, and excellence. Our overarching mission is to create economic opportunities so that people have better lives. We foster an environment where individuals are encouraged to bring their authentic selves to work, nurturing personal and professional growth through development opportunities, mentorship programs, and participation in Upwork Belonging Communities.

We take pride in providing exceptional benefits to our employees. These include comprehensive medical insurance coverage for both you and your family, unlimited paid time off, a 401(k) plan with matching contributions, 12 weeks of paid parental leave, and an Employee Stock Purchase Plan. To explore these benefits in detail, as well as gain insights into our company values, working principles, and the overall employee experience, we invite you to visit our Life at Upwork page.

Check out our Careers page to learn more about the employee experience.

Upwork is proudly committed to recruiting and retaining a diverse and inclusive workforce. As an Equal Opportunity Employer, we never discriminate based on race, religion, color, national origin, gender (including pregnancy, childbirth, or related medical condition), sexual orientation, gender identity, gender expression, age, status as a protected veteran, status as an individual with a disability, or other applicable legally protected characteristics.