Senior Frontend Engineer

We are looking for a skilled Frontend Engineer to join our engineering team. Requirements: 6+ years of professional experience in frontend/full-stack product development, with 5+ years of React in production and strong senior-level expertise in TypeScript, including strict mode, React 19, and modern tooling such as Vite and monorepos.2+ years of Node.js development on the server, with hands-on experience building and operating BFF or API gateway layers. Experience with NestJS is a strong plus; what matters most is understanding service aggregation, authentication, pagination, error contracts, and clear BFF boundaries.Strong production experience in microservice environments — ideally working with 10+ services and able to explain why a BFF exists, what it should own, and where its boundary sits. Experience limited to consuming a single monolithic API is not sufficient.Experience building complex, stateful UIs, such as graph/canvas editors or collaborative interfaces, including patterns like undo/redo, optimistic updates, conflict handling, and other non-trivial state management.Strong frontend architecture and code organization skills — familiar with approaches such as FSD or modular/layered architectures, and comfortable working within an established team architecture rather than imposing a personal one.Strong product sense and autonomy — able to make reasonable UI and UX decisions from product context and an existing design system, without always relying on finished designs or dedicated product designers.Solid testing culture, with hands-on experience writing and maintaining unit/component tests with Vitest and end-to-end tests with Playwright as an integral part of development.Hands-on experience with modern frontend/data tools, including React Query, Socket.io, Prisma and PostgreSQL.Hands-on experience with AI-assisted development tools such as Claude Code, Cursor, Codex, GitHub Copilot, or similar agentic coding tools. Comfortable understanding where AI agents add value and where they require human oversight, and working in development workflows where agent instructions and automated reviews are integrated into the repository/CI. Nice to have Experience owning or maintaining a shared component library used by multiple product teams, or migrating a legacy UI to a new design system while continuing feature development.Experience with real-time collaboration technologies, such as Yjs, Automerge, or operational transforms.Experience with WebRTC or SIP in the browser, particularly for voice applications, audio review interfaces, waveforms, or transcript synchronization.Experience with Prisma or Kysely and hands-on PostgreSQL query optimization/work.Experience with Kubernetes/Helm and observability tooling such as OpenTelemetry or Prometheus.Domain experience in voice AI, telephony, contact centers, conversational AI, or LLM-based products. Responsibilities: Build and evolve React interfaces for our AI agent platform, including conversation and prompt engineering tools, graph-based collaborative flow builders, agent configuration and testing interfaces, and call analytics dashboards, based on Figma designs.Own and develop the BFF layer on NestJS, aggregating REST microservices through typed clients generated from OpenAPI. Handle authentication, pagination, streaming, and error contracts to keep the frontend layer thin. Also contribute to backend development with PostgreSQL and Redis.Drive the evolution and consistency of our frontend component ecosystem: consolidate legacy Ant Design components into our own design system built on Mantine, own the shared UI library and Storybook, and keep multiple product applications consistent.Ensure product quality through comprehensive testing, using Vitest for unit/component tests and Playwright for end-to-end and critical user-flow testing, including SDK functionality.Collaborate across teams and product v-teams on API contracts, SDK protocols, code reviews, bug fixes, QA support, and test scenarios, joining initiatives where frontend or platform expertise is needed.Partner with the documentation team to create and maintain comprehensive documentation, including integration guides and practical code examples. What we offer: The team has built award-winning AI products for tech corporations - devices, voice assistants, products that are actually in the world Cutting-edge tech stack: Speech Technologies, NLP, Generative AI (LLMs, diffusion models), voice-first agentic architecture with privacy-first and on-premises deploymentHigh engineering bar and real ownership - the team cares about what actually works in production, not what looks good in a demo, and you'll see the impact of your work directly Fast career progression - a senior-heavy team and a high volume of real problems means you grow faster than you would anywhere else Startup pace with enterprise stability - real clients, real revenue, no bureaucracy Fully remote across Europe21 vacation days + public holidays + 5 sick days Private English lessons via Preply