Sr. Full-Stack Engineer (Frontend Heavy)

Senior Full-Stack Engineer (Frontend-Heavy)Location: Irvine, CA 92618Work Style: Hybrid (3 days/week in office)Work Hours: 9:00 AM – 6:00 PM Salary Range: $110,000 – $120,000 baseExperience Level: 5–10 yearsWork Authorization Requirement: Due to company policy, we are unable to provide visa sponsorship now or in the future.Candidates must be legally authorized to work in the United States on a permanent basis.　Applicants requiring visa sponsorship cannot be considered.About the CompanyA growing software company based in Irvine, California is seeking a Senior Full-Stack Engineer to help expand and evolve a modern B2B customer support and ticketing platform primarily serving Japanese business customers.This is a unique opportunity to join a small, collaborative product team where your work directly impacts customers and product direction. The team works closely with global counterparts and values ownership, technical excellence, and thoughtful product development. The RoleWe are looking for a Senior Full-Stack Engineer with strong frontend expertise to help build and scale a modern SaaS platform. This is a full-stack role with a strong emphasis on React + TypeScript frontend development, while also contributing to backend APIs and platform architecture as needed.You will collaborate closely with engineering, product, and leadership teams to deliver scalable, high-quality user experiences and technical solutions.What You’ll DoModernize and scale a React + TypeScript application while improving architecture and code qualityBuild and expand a reusable UI component library using MUIDesign and improve frontend state management and data-fetching architectureDrive frontend performance improvements including code splitting, lazy loading, caching, and optimizationDevelop responsive and polished user experiences across devices and screen sizesDeliver full-stack features from backend APIs through frontend implementationImprove and maintain backend services including REST APIs, GraphQL APIs, background workers, and scheduled jobsEstablish engineering best practices, code review standards, and scalable development patternsCollaborate closely with cross-functional and international teamsTechnology StackFrontendReact, TypeScript, MUI, TipTap (rich-text editing)BackendNode.js, Bun, REST API, GraphQLInfrastructure & DataPostgreSQL, Redis, RabbitMQ, Meilisearch, Qdrant, Docker, KubernetesAdditionalAI-powered platform featuresRequired Qualifications7+ years of software engineering experienceStrong recent experience with React and TypeScript- You have led and taken ownership of complex React applications, not just contributed as part of a larger team.Deep understanding of modern React concepts including:Hooks, Suspense, Code splitting, Lazy loading, Performance optimizationStrong experience with frontend state management and caching strategiesExperience modernizing and scaling production applicationsSolid understanding of responsive UI development and modern CSSExperience building accessible and polished user interfacesFull-stack development experience including backend development with Node.js or similar technologiesExperience working with relational databases such as PostgreSQLStrong communication and collaboration skillsAbility to work independently within a small agile teamBusiness-level English communication skillsPreferred QualificationsExperience with GraphQL (Apollo, urql, etc.) or tRPCExperience with Bun, Hono, or modern JavaScript runtimes/frameworksFamiliarity with RabbitMQ, Meilisearch, or vector databasesExperience with Docker and KubernetesExperience building or maintaining design systems/component librariesFamiliarity with TipTap or ProseMirrorReact Native or mobile development experienceExperience working on SaaS, B2B, or ticketing/support platformsJapanese language skills are a plusWork EnvironmentHybrid schedule: 3 days/week onsite in Irvine, CACollaborative and highly technical small-team environmentOpportunity for meaningful ownership and direct product impactLong-term growth opportunity within an expanding product organization