Research Engineer, Applied Research

Salary: $211,000 - 251,000 per year Requirements:

• Strong experience building and deploying production machine learning and AI systems, with experience in areas such as applied ML, search, ranking, recommendations, advertising, language, or speech.
• Excellent judgment in translating product challenges into machine learning problems and choosing effective, appropriately simple solutions.
• Experience working deeply with data, experimentation, evaluation, and iterative model development.
• A practical, evidence-based approach to deciding when modeling is needed and when a simpler solution is preferable.
• Ability to take initiative and work across the technology stack to achieve outcomes.
• Alignment with our values, including craftsmanship, customer obsession, and intensity.
• A degree in computer science, machine learning, or a related field, or equivalent professional experience.
• Additional strengths include experience with supervised fine-tuning or reinforcement learning; search, ranking, recommendation, or advertising systems; training and deploying language, speech, or multimodal models; designing evaluations tied to real-world product outcomes; large-scale consumer datasets or high-volume ML products; or contributing to applied ML research or benchmarks.

• Address unsolved applied AI and machine learning challenges in post-training, voice AI, and long-horizon task execution, building agents that can reason, adapt, and complete complex customer tasks reliably.
• Decide when to build specialized models and when to use externally provided frontier intelligence, balancing quality, speed, and cost for customer value.
• Turn ambiguous product and customer needs into clearly framed machine learning problems.
• Develop, fine-tune, evaluate, and deploy models that improve our customer-facing AI agents.
• Advance our post-training methods, from supervised fine-tuning toward reinforcement learning and long-horizon optimization.
• Create rigorous evaluations that connect model performance with real-world agent quality.
• Work with large proprietary datasets spanning text and audio interactions.
• Collaborate across our company to take ideas from experimentation through production deployment and customer impact.

• AI
• AI Agents
• Fine-tuning
• Machine Learning
• Salesforce
• CTO
• Support
• VR

More:

We are Sierra, a platform for customer-facing AI agents, and we work with major brands to transform how they serve customers and grow their businesses. Our Applied Research team improves the quality, speed, and cost efficiency of the models behind our agents, bringing research advances into reliable production systems. We are primarily an in-person company based in San Francisco, with offices across North America, Europe, and Asia. Our co-founders are Bret Taylor and Clay Bavor, who bring experience from organizations including Salesforce, Facebook, and Google. Our culture is guided by trust, customer obsession, craftsmanship, intensity, and family, and we value a diverse team with varied skills and experiences. For full-time employees, we offer flexible paid time off, health and insurance benefits, retirement plans according to location, parental and family-building benefits, meals and refreshments, a discretionary benefit stipend, and equity-plan participation for eligible employees; benefits vary by region and may change.

last updated 41 week of 2026