Senior Data Scientist (Hybrid @ Bellevue, WA or Remote @ Florida)

OfferUp • Bellevue, FL

2d • $190,000 - $220,000 • Hybrid

About The Position

OfferUp is looking for a Senior Data Scientist to join our Data team and serve as a key architect of our marketplace intelligence. In this role, you will move beyond building models to defining the logic of the customer journey and driving the technical strategy for our most complex business problems. From optimizing search ranking and recommendation engines to pioneering fraud detection and generative AI features, your work will have a company-wide impact and be critical to OfferUp’s success as the leading local marketplace. We are looking for a Senior Data Scientist to join our Data team . This team is tasked with building the core intelligence—from search ranking and recommendation engines to fraud detection and generative AI features—that is critical to OfferUp’s success as the leading local marketplace.

Requirements

• 5+ years of building and shipping ML models and data solutions with quality.
• 4+ years of professional software development in Python.
• Strong proficiency in querying and retrieving data using SQL from large-scale distributed systems.
• Ph.D. or Master’s Degree in Computer Science, Mathematics, Statistics, or a related technical field OR Bachelor’s degree and relevant work experience.
• Deep understanding in a classical NLP method (e.g. n-grams, NER, POS tagging) and ML tasks (e.g. semantic analysis, text classification).
• Impact-oriented: Experience delivering end-to-end projects that solve complex business problems.
• Strong communication skills, with the ability to explain technical concepts to non-technical stakeholders.
• Proven track record of mentoring junior or mid-level team members and performing high-quality code and design reviews.
• Collaborative mindset with experience contributing to project roadmaps and technical documentation.

Nice To Haves

• Practical experience with LLMs, deep models (RNN, LSTM) and their applications is highly preferred.
• Proficiency in deep learning frameworks such as PyTorch, TensorFlow or Keras.
• Experience training models in cloud environments (Databricks/Sagemaker preferred).
• Experience deploying models as microservices within cloud infrastructure (AWS preferred).
• Hands-on experience with Spark for large-scale data processing.
• Working knowledge of deep learning methods applied to images (CNNs, ResNet).

Responsibilities

• Lead the research, design, and implementation of end-to-end machine learning solutions, from initial hypothesis and data exploration to A/B testing and production deployment.
• Own the evaluation and "prompt engineering" strategy for Large Language Models (LLMs) to enhance product features like automated categorization and user communication.
• Act as a strategic partner to Product and Engineering leaders, translating business goals into data science roadmaps that prioritize long-term customer experience over short-term gains.

Benefits

• health insurance
• healthcare savings and spending accounts
• retirement savings benefits (401(k) plan with match)
• basic and voluntary life insurance
• disability benefits
• paid time off for sick leave, family and/or medical leave, vacation, and 12 company holidays

What This Job Offers

• Job Type: Full-time
• Career Level: Senior
• Number of Employees: 251-500 employees