Software Engineer, Applied AI - Frontier Engineering

ABOUT MERCOR Mercor's mission is to organize human intelligence to power the AI economy. We're a leading AI data company, building the layer between human expertise and frontier models. Millions of domain experts on the platform are paid over $4 million per day to train frontier AI models. Mercor's APEX benchmark family measures AI's real-world impact on professional work. Mercor Enterprise brings this same infrastructure to Fortune 500 companies: helping companies capture how their best people actually work, translating that expertise directly back into agents.   Mercor is creating a new category of work where expertise powers AI advancement. Achieving this requires an ambitious, fast-paced and deeply committed team. You’ll work alongside researchers, operators, and AI companies at the forefront of shaping the systems that are redefining society. Mercor is a profitable Series C company valued at $10 billion. We work in-person five days a week in our San Francisco, NYC, or London offices. ABOUT THE ROLE As a Software Engineer on Applied AI, you’ll build, deploy, and operate systems that sit directly between frontier AI research and data delivery. This is a high-ownership, deeply technical role. You’ll work through ill-defined problems, prototype quickly with researchers and customers, and take systems from early experiments to reliable, scalable production. You’ll own projects end-to-end: spanning requirements gathering, creating data creation pipelines, and improving model-adjacent infrastructure, while partnering closely with frontier AI labs and Mercor’s internal teams to ship high-impact applied AI solutions. WHAT YOU’LL DO - Partner closely with frontier AI labs to understand their data, post-training, and evaluation needs - Build and operate scalable data pipelines for post-training workflows and model evaluations - Design and build scalable systems for synthetic data generation and data quality, and work directly with customers to understand requirements and develop technical solutions - Prototype new data types, benchmarks, and evaluation frameworks - Lead technical discussions with customers WHAT MAKES THIS ROLE DIFFERENT - Direct frontier exposure. You’ll work closely with researchers at leading AI labs, building infrastructure that directly accelerates cutting-edge research. - Coding + customer work. This role blends deep technical execution with customer interaction. Engineers who enjoy both building and communicating tend to thrive. DAY-TO-DAY - Fast-moving, high-ownership environment - Technically demanding, collaborative work - “Building the plane while flying it” - In-person culture (SF, 181 Fremont) - Aligned with frontier research timelines WHAT WE’RE LOOKING FOR - Strong backend engineering fundamentals in a modern language (Python, Go, Rust, etc.) - Experience with model training and inference - Strong grounding in statistical analysis and experimental design for measuring model performance and improvements - Familiarity with evaluation methods for large language models - Comfort working through ambiguity and shipping iteratively YOU’RE LIKELY SOMEONE WHO - Enjoys ownership and customer-facing problem solving - Thinks entrepreneurially and moves quickly - Balances speed with engineering rigor - Communicates clearly with technical and non-technical users WHY ENGINEERS JOIN - Direct exposure to frontier AI research - Real ownership and visible impact - Technical depth paired with human interaction - Fast feedback loops and high leverage - There are very few roles that combine this level of technical rigor, customer proximity, and research exposure. BENEFITS - Bi-annual performance bonus structure - Generous equity grant vested over 4 years - Up to $15k Relocation bonus - $10K proximity bonus (if you live within 0.5 miles of our office) - $1.5K monthly stipend for meals - Free Equinox membership - $200 monthly laundry reimbursement - $200 monthly personal wellness reimbursement - Health, Dental, Vision insurance