Backend Engineer, Marketplace at Mercor

ABOUT MERCOR Mercor is defining the future of work. We partner with leading AI labs and enterprises to provide the human intelligence essential to AI development. Our vast talent network trains frontier AI models in the same way teachers teach students: by sharing knowledge, experience, and context that can't be captured in code alone. Today, more than 30,000 experts in our network collectively earn over $2 million a day. 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 MERCOR Mercor is defining the future of work. We partner with leading AI labs and enterprises to provide the human intelligence essential to AI development. Our vast talent network trains frontier AI models in the same way teachers teach students: by sharing knowledge, experience, and context that can't be captured in code alone. Today, more than 30,000 experts in our network collectively earn over $2 million a day. 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 new San Francisco headquarters. About the Role As a Backend Engineer on the Marketplace team, you will build the core systems that govern how talent and opportunities meet on Mercor. You’ll work on search, matching, allocation, and workflow infrastructure at the heart of the marketplace, where system quality directly affects fill rate, hiring speed, and revenue. The problems are technically demanding and tightly coupled to business outcomes: latency, reliability, throughput, and system quality all directly affect marketplace performance. What You’ll Build • Backend services that power candidate-job matching, routing, and marketplace workflows • APIs and internal systems for search, eligibility, scoring, allocation, and fulfillment • Data models and system abstractions for a rapidly evolving labor marketplace • Infrastructure for real-time and asynchronous decisioning at high volume • Operational systems and tooling that keep product-critical workflows reliable, observable, and easy to evolve Example Problems • Build the systems that determine which candidates are eligible for which opportunities • Design matching and allocation infrastructure that balances speed, quality, and fill rate • Improve the performance and reliability of APIs serving marketplace decisions in real time • Develop workflow engines for onboarding, vetting, routing, and placement • Design backend abstractions that let product and ML teams iterate quickly without degrading system quality What We’re Looking For • Track record of building and operating reliable backend systems in production • Strong judgment in system design, performance, reliability, and data modeling • Comfort working on high-throughput APIs, distributed systems, and asynchronous workflows • Ability to translate product and marketplace requirements into clean technical systems • High engineering standards and a bias toward simple, durable abstractions Nice to Have • Experience with search, recommendation, matching, scheduling, or marketplace systems • Experience supporting ML-powered products or integrating model inference into production systems • Familiarity with event-driven architecture, queues, caching, and observability tooling Why This Role This role sits on a core decision layer of the product. Your work will directly shape how the marketplace operates: which opportunities get filled, how quickly hiring happens, and how reliably the system scales as volume and complexity increase. Tech Stack Python, Go, Kafka, Postgres, Redis, Elasticsearch, Kubernetes, Terraform Benefits - Generous equity grant vested over 4 years - A $10K housing bonus (if you live within 0.5 miles of our office) - A $1.5K monthly stipend for meals - Free Equinox membership - Health insurance