LLM Platform Engineer

Whatnot•Los Angeles, CA

6d•$225,000 - $320,000•Hybrid

About The Position

Whatnot is looking for builders–intellectually curious, highly entrepreneurial engineers eager to shape the future of AI and ML at Whatnot. You’ll design and scale the core infrastructure that powers large language model applications across the company, working side by side with machine learning scientists to bring cutting-edge models into production and unlock entirely new product experiences. This means building systems that make AI dependable and fast at scale–from building retrieval systems to more effectively ground LLM responses in Whatnot’s business context to developing scalable LLM evaluation frameworks and human-in-the-loop feedback mechanisms.

Requirements

4+ years of professional experience developing machine learning systems and algorithms, plus:
Bachelor’s degree in Computer Science, Statistics, Applied Mathematics or a related technical field, or equivalent work experience.
3+ years of software engineering experience building and maintaining production systems for consumer-scale loads.
1+ years of professional experience developing software in Python
Ability to work autonomously and drive initiatives across multiple product areas and communicate findings with leadership and product teams.
Experience with operational, search, and key-value databases such as PostgreSQL, DynamoDB, Elasticsearch, Redis.
Firm grasp of visualization tools for monitoring and logging e.g. DataDog, Grafana.
Familiarity with cloud computing platforms and managed services such as AWS Sagemaker, Lambda, Kinesis, S3, EC2, EKS/ECS, Apache Kafka, Flink.
Professionalism around collaborating in a remote working environment and well tested, reproducible work.
Exceptional documentation and communication skills.

Responsibilities

Own the infrastructure powering LLMs across critical business surfaces– supporting growth, recommendations, trust and safety, fraud, seller tooling, and more.
Create robust and scalable LLM evaluation frameworks to measure model performance, guide iteration, and prevent regression via CI/CD.
Deploy RAG systems and MCP servers to more effectively ground LLM responses in Whatnot’s business context while enforcing rigorous PII controls.
Design efficient human-in-the-loop feedback pipelines that can be used to inform scalable LLM evaluation
Bridge the gap between research and production, helping to transform experimental ideas into scalable solutions
Stretch beyond your comfort zone to take on new technical challenges as we scale AI across Whatnot’s ecosystem.
US Based: We offer flexibility to work from home or from one of our global office hubs, and we value in-person time for planning, problem-solving, and connection. Team members in this role must live within commuting distance of our New York, Seattle, Los Angeles, and San Francisco hubs.

Benefits

Flexible Time off Policy and Company-wide Holidays (including a spring and winter break)
Health Insurance options including Medical, Dental, Vision
Work From Home Support
Home office setup allowance
Monthly allowance for cell phone and internet
Care benefits
Monthly allowance for wellness
Annual allowance towards Childcare
Lifetime benefit for family planning, such as adoption or fertility expenses
Retirement; 401k offering for Traditional and Roth accounts in the US (employer match up to 4% of base salary) and Pension plans internationally
Monthly allowance to dogfood the app
All Whatnauts are expected to develop a deep understanding of our product. We're passionate about building the best user experience, and all employees are expected to use Whatnot as both a buyer and a seller as part of their job (our dogfooding budget makes this fun and easy!).
Parental Leave
16 weeks of paid parental leave + one month gradual return to work company leave allowances run concurrently with country leave requirements which take precedence.