Software Engineer, Frontend

Mercor

Location: San Francisco, United States
Job Type: full-time
Salary: $130K – $500K
Posted: December 1, 2025

Job Description

About Mercor

Mercor is at the intersection of labor markets and AI research. 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 $1.5 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 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

Generous equity grant vested over 4 years
A $20K relocation bonus (if moving to the Bay Area)
A $10K housing bonus (if you live within 0.5 miles of our office)
A $1K monthly stipend for meals
Free Equinox membership
Health insurance

🎯 Who is this job for?

This position is ideal for a skilled frontend engineer with solid experience in React, Next.js, and TypeScript who wants to build high-impact, production-grade interfaces in a fast-moving, deeply product-focused environment. It’s a strong match for someone who enjoys owning features end to end, collaborating closely with design and backend teams, and turning complex workflows into intuitive, high-performance UI. This role will appeal to engineers who thrive on solving challenging problems with elegance and simplicity, working onsite with a highly ambitious team, and contributing directly to the systems that power training, evaluation, and scale for leading AI labs.

💬 Potential Interview Questions

What frontend stack are you most comfortable with for building production-grade web apps?
React with TypeScript and Next.js, styled with Tailwind or CSS Modules, using modern build tools like Vite or Webpack.
How do you structure a scalable React/Next.js codebase?
I use a feature-based or domain-driven folder structure, co-locate hooks and components, centralize shared UI and utilities, and keep server vs client concerns clearly separated.
How do you handle data fetching and state management in a Next.js application?
I use Next.js data-fetching methods (server components, fetch, route handlers) for server state, and hooks or a lightweight store (Context/Zustand/Redux) for client state, with clear loading/error handling.
What techniques do you use to keep a complex UI performant?
I rely on memoization (React.memo, useMemo, useCallback), code splitting and lazy loading, efficient list rendering (virtualization), and profiling with React DevTools and browser performance tools.
How do you go from a Figma wireframe to a production-ready UI?
I break the design into reusable components, implement them with semantic HTML and responsive layout, map all states (loading/empty/error), and refine interactions together with design and product.
How do you integrate REST or GraphQL APIs cleanly into the frontend?
I create a typed API layer (using fetch/Axios or a GraphQL client), encapsulate request logic in hooks or services, and standardize error handling, retries, and data transformation.
What’s your approach to building a good UX for data-heavy or real-time interfaces?
I prioritize information hierarchy, progressive disclosure, clear feedback on actions, optimistic updates where appropriate, and smooth real-time updates without overwhelming the user.
How do you ensure code quality in a fast-moving product team?
I use TypeScript for type safety, write unit/integration tests (Jest/RTL), enforce linting and formatting in CI, keep PRs small and focused, and use code reviews to maintain shared standards.
How do you handle ambiguous product requirements when starting a feature?
I clarify the core user problem and success metrics with product/design, propose a simple MVP version, document assumptions, and iterate quickly based on real user feedback.
What interests you about building frontend systems for AI-focused products at Mercor?
I’m excited by the challenge of making complex AI workflows intuitive and reliable, and by the chance to design UIs that directly shape how leading labs train and evaluate frontier models.

📋 Job Summary

Mercor is hiring a Software Engineer, Frontend (On-site, San Francisco) to build high-impact React/TypeScript (Next.js) interfaces that define how top AI labs interact with their core AI and human data infrastructure. You’ll design and ship intuitive, performant UIs end-to-end, integrating with backend APIs and working closely with product and design on both talent platform features and applied AI data tools. This full-time, in-office role offers $130K–$500K in total compensation with equity, plus standout perks like a $20K relocation bonus, $10K housing bonus near HQ, $1K monthly meal stipend, Equinox membership, and health insurance. Join a profitable $10B Series C company where your work directly powers how OpenAI-, Anthropic-, and Google-level teams train and evaluate frontier models.