At a glance
- Employment
- Full-time
- Workplace
- Onsite
- Location
- San Francisco
About Sierra
- Sierra is the leading platform for customer-facing AI agents, working with many of the world's biggest brands — including The GAP, Rocket Mortgage, SoFi, Sutter Health, and SoftBank — to transform how they serve customers and grow their businesses. We are primarily an in-person company based in San Francisco, with growing offices across North America, Europe, and Asia.
- We are guided by a set of values that are at the core of our actions and define our culture: Trust, Customer Obsession, Craftsmanship, Intensity, and a commitment to balancing Family along the way. These values are the foundation of our work, and we are committed to upholding them in everything we do.
- Our co-founders are Bret Taylor https://www.linkedin.com/in/brettaylor/ and Clay Bavor https://www.linkedin.com/in/claybavor/. Bret currently serves as Board Chair of OpenAI. Previously, he was co-CEO of Salesforce (which had acquired the company he founded, Quip) and CTO of Facebook. Bret was also one of Google's earliest product managers and co-creator of Google Maps. Before founding Sierra, Clay spent 18 years at Google, where he most recently led Google Labs. Earlier, he started and led Google’s AR/VR effort, Project Starline, and Google Lens. Before that, Clay led the product and design teams for Google Workspace.
- Sierra’s Applied Research team advances the quality, speed, and cost efficiency of the models powering our agents across a wide range of tasks. Our work spans post-training open-weight models for specialized capabilities and pioneering new approaches to voice AI, turning research breakthroughs into reliable production systems.
About the role
- Sierra is seeking a Research Engineer for their Applied Research team to advance the quality, speed, and cost efficiency of the models powering their AI agents.
- The role involves tackling unsolved applied AI and ML problems, including post-training, voice AI, and long-horizon task execution.
- The position is based in San Francisco as part of an in-person company.
Responsibilities
- Tackle unsolved applied AI and ML problems, pushing the boundaries of post-training, voice AI, and long-horizon task execution.
- Determine when to build specialized models and when to use externally provided frontier intelligence, balancing quality, speed, and cost.
- Turn ambiguous product and customer problems into well-framed machine learning problems.
- Develop, fine-tune, evaluate, and deploy models that improve Sierra’s customer-facing AI agents.
- Advance post-training work, from supervised fine-tuning toward 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 Sierra while taking ideas from experimentation through production deployment and customer impact.
Requirements
- Strong experience building and deploying production machine learning and AI systems.
- Excellent judgment in framing product problems as ML tasks and selecting the simplest and most effective approach.
- Experience working deeply with data, experimentation, evaluation, and model iteration.
- A practical, evidence-driven approach to ML, with strong judgement around when a problem calls for modeling and when a simpler solution will deliver the best outcome.
- The ability to operate with high agency and work across the stack when needed to deliver an outcome.
- Alignment with Sierra’s values, including Craftsmanship, Customer Obsession, and Competitive Intensity.
- A degree in computer science, machine learning, or a related field, or equivalent professional experience.
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, as well as delicious snacks and coffee to keep you energized
- Discretionary benefit stipend giving people the ability to spend where it matters most
- Free alphorn lessons
- Eligible full-time employees can participate in Sierra's equity plans
Workplace
- Primarily an in-person company based in San Francisco
Skills
- Machine Learning
- Applied AI
- Supervised Fine-Tuning
- Reinforcement Learning
- Voice AI
