Research Engineer, Applied Research
San Francisco, CA • FullTime
Posted 2h ago
Job Location
San Francisco, CA
Tech Stack
Remote Work Policy
On-site
Employment Type
FullTime
Categories
Applied AI Engineer
About the job
Sierra is seeking a Research Engineer to join its Applied Research team, focused on advancing the quality, speed, and cost-efficiency of AI agents. This role involves pushing the boundaries of post-training, voice AI, and long-horizon task execution to build agents that can reason, adapt, and reliably perform complex tasks. You will determine the optimal approach for model development, balancing quality, speed, and cost to deliver customer value, and translate ambiguous product and customer problems into well-defined machine learning challenges. The position requires developing, fine-tuning, evaluating, and deploying models, advancing post-training techniques, and building rigorous evaluations to link model performance with real-world agent quality. You will work with large-scale, proprietary text and audio datasets and collaborate across teams to bring ideas from experimentation to production.
Responsibilities
- Tackle unsolved applied AI and ML problems, focusing on post-training, voice AI, and long-horizon task execution.
- Build agents capable of reasoning, adapting, and reliably carrying out complex tasks.
- Determine when to build specialized models versus using external frontier intelligence, optimizing for quality, speed, and cost.
- Translate ambiguous product and customer problems into well-framed machine learning problems.
- Develop, fine-tune, evaluate, and deploy models to enhance customer-facing AI agents.
- Advance post-training methodologies, including supervised fine-tuning, reinforcement learning, and long-horizon optimization.
- Build rigorous evaluations that connect model performance to real-world agent quality.
- Work with large-scale, proprietary datasets spanning text and audio interactions.
- Collaborate across teams to move ideas from experimentation through production deployment and customer impact.
Requirements
- Strong experience building and deploying production machine learning and AI systems.
- Backgrounds in applied ML, including search, ranking, recommendations, advertising, language, and speech are welcome.
- Excellent judgment in framing product problems as ML tasks and selecting the simplest & most effective approach.
- Experience working deeply with data, experimentation, evaluation, and model iteration.
- A practical, evidence-driven approach to ML, with strong judgment around when modeling is necessary versus a simpler solution.
- Ability to operate with high agency and work across the stack when needed.
- Alignment with company values: Craftsmanship, Customer Obsession, and Competitive Intensity.
- A degree in computer science, machine learning, or a related field, or equivalent professional experience.
- Experience with supervised fine-tuning or reinforcement learning.
- Experience in search, ranking, recommendations, or advertising systems.
- Experience training and deploying language, speech, or multimodal models.
- Experience designing model evaluations tied to real-world product outcomes.
- Experience working with large-scale consumer datasets or high-volume ML products.
- Contributions to applied ML research or benchmarks.
Benefits
- Flexible (unlimited) paid time off
- Medical, dental, and vision benefits for you and your family
- Life insurance and disability benefits
- Retirement plan dependent on country of employment
- Parental leave
- Fertility and family building benefits through Carrot
- Lunch, snacks, and coffee
- Discretionary benefit stipend
- Free alphorn lessons