Software Engineer, Frontend

Mercor · San Francisco

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Frontend San Francisco Posted Oct 2, 2025 130,000 – 500,000 USD

About Mercor

Mercor's mission is to organize human intelligence to power the AI economy. 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 the Role

As a Frontend Engineer at Mercor, you’ll join a small, product-driven engineering team designing and building the user-facing systems that define how customers interact with our core AI infrastructure. This is a high-impact, product-focused role where you’ll work closely with design, product, and backend engineers to ship intuitive, performant, and scalable experiences for the world’s leading AI labs. From day one you’ll write production-grade code, own projects end-to-end, and balance velocity with polish, usability, and scalability.

At the end of the process, you’ll be team-matched to where you can have the most impact, on one of the following:

Talent platform side – building next-generation tools that automate recruiting end-to-end, intelligently match candidates to roles, and power global hiring with seamless contracts and payments.
Applied AI/human data side – partnering with top AI researchers from OpenAI, Anthropic, Google, and others to create post-training datasets that improve foundational model capabilities.

What You’ll Do

Design and build intuitive, performant user interfaces that scale across platforms.
Integrate APIs and data flows seamlessly with backend systems.
Collaborate with design and product teams to take concepts from wireframes to production.
Write clean, maintainable React/TypeScript code and contribute to frontend documentation.
Participate in design reviews, code reviews, and retrospectives.
Solve complex product and technical challenges under real-world constraints.
Contribute to systems that power training, evaluation, and scaling for leading AI labs.

What We’re Looking For

Strong coding fundamentals and proficiency in JavaScript/TypeScript (React + Next.js stack).
Understanding of frontend architecture, state management, and design patterns.
Familiarity with APIs, data fetching, and performance optimization.
Ability to thrive in ambiguous, fast-moving environments with high ownership.
Strong design sense and empathy for end-users.
Curiosity, grit, and a bias toward simple solutions to complex problems.
Strong communication skills and ability to articulate technical and product tradeoffs.
Excited and curious about Mercor.

Nice-to-Haves

Experience with frontend frameworks (React, Next.js, Tailwind) and modern build tools.
Exposure to AI tools, LLM-powered products, or projects in this space.
Experience at top-tier tech companies or fast-scaling startups.
Contributions to open source or shipped side projects.
Background in design systems, accessibility, or developer tooling.
Exposure to real-time data, visualization libraries, or high-performance UI.

Why Mercor

Impact: Your work powers how the world’s leading AI labs train and test their models.
Learning: Get early insights into frontier model capabilities months before the market.
Growth: Work on both infrastructure and research-adjacent projects with fast paths to ownership.

Benefits