Front End Developer - Design Systems

Kforce has a client in Foster City, CA that is seeking a Front End Developer - Design Systems who cares about the craft of a user interface, someone who notices when an easing curve is wrong, when a focus state is missing, when spacing is off by two pixels.

Summary:

Join a team that builds and maintains the component library every one of our applications is built on. Part of that system deals with 3D objects, so Three.js experience matters here. This means working to very specific design specifications. Our designers hand off detailed specs in Figma, and we expect you to implement them faithfully. It also means pushing back when the spec is wrong: if there's a better way to build something, or a technical reason the design won't hold up, we want you to say so and explain why. You're expected to use AI heavily in this role, and to review every line it generates before it goes upstream. Part of the job is building the guardrails that make AI-generated code consistent with our style and conventions at scale.

Duties:

• Build and maintain React components alongside the rest of the team, from primitives through complex composite components
• Implement designs to spec from Figma, with precision, states, transitions, responsive behavior, and light and dark modes
• Contribute to Storybook: write and maintain stories, keep documentation current, and help keep the library genuinely usable by the engineers who consume it
• Write component tests with Vitest and Testing Library, and end-to-end and visual regression coverage with Playwright, all running in CI
• Implement motion and animation, CSS transitions and keyframes, and WebGL where the experience calls for it
• Build the AI harness: the prompts, rules, linting, type constraints, and review workflow that keep generated code consistent with our conventions
• Partner daily with designers and other engineers, review specs before implementation, flag problems early, and review pull requests
• 4+ years of frontend development experience, including significant time working on a component library or design system
• Deep React expertise, composition patterns, hooks, performance, and the discipline of designing component APIs that other engineers have to live with
• Genuine craft sensibility; You care how an interface feels, not just whether it renders; Interaction states, motion, and detail are part of the work, not polish applied at the end
• Three.js experience, highly desired; Part of our system is 3D, and we need someone who can build and maintain those components rather than route around them
• Proven ability to work from detailed design specifications, and comfort in Figma, reading specs, inspecting values, and knowing where to look for intent
• An opinion, and the ability to defend it; You can tell a designer why a different approach is better, make the case clearly, and then commit to whatever the team decides
• Strong CSS, including animation and transitions
• Ample experience testing components with Vitest and Testing Library at the individual pattern level, plus Playwright for end-to-end and snapshot testing, and solid working knowledge of CI pipelines
• Familiarity with design tokens and how to structure them so one source of truth can feed Web, iOS, and Android
• Extensive hands-on experience with AI coding tools, and clear judgment about their output; You use them constantly, and you review everything before pushing
• Demonstrable experience collaborating with designers and other engineers; We'll ask about specific projects and how those relationships worked

Nice to have:

• Working knowledge of MUI, theming, overrides, and extending it without fighting it; Familiarity is enough - depth is a plus
• Experience building custom tooling around AI agents: MCP servers, Skills, custom linting, or codegen
• Experience with React Three Fiber or similar React/Three.js bindings

The pay range is the lowest to highest compensation we reasonably in good faith believe we would pay at posting for this role. We may ultimately pay more or less than this range. Employee pay is based on factors like relevant education, qualifications, certifications, experience, skills, seniority, location, performance, union contract and business needs. This range may be modified in the future.

We offer comprehensive benefits including medical/dental/vision insurance, HSA, FSA, 401(k), and life, disability & ADD insurance to eligible employees. Salaried personnel receive paid time off. Hourly employees are not eligible for paid time off unless required by law. Hourly employees on a Service Contract Act project are eligible for paid sick leave.

Note: Pay is not considered compensation until it is earned, vested and determinable. The amount and availability of any compensation remains in Kforce's sole discretion unless and until paid and may be modified in its discretion consistent with the law.

This job is not eligible for bonuses, incentives or commissions.

Kforce is an Equal Opportunity/Affirmative Action Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, pregnancy, sexual orientation, gender identity, national origin, age, protected veteran status, or disability status.

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