Senior Frontend Engineer

Clera · Berlin💰 $7,500–$13,333 USD/messenior

In short

▸Construyes interfaces rápidas para visualizar trazas de LLM masivas en tiempo real.
▸Optimizas React: virtualización, memoización y arquitectura de componentes para manejar datos de miles de tokens.
▸Trabajo remoto en Europa con reuniones presenciales mensuales en Berlín, alta autonomía y impacto directo.

🌐 Fluent English communication skills; able to collaborate effectively across EU timezones

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What they ask for

✓5+ años de experiencia en desarrollo frontend en aplicaciones web en producción
✓Permiso de trabajo en la UE sin sponsorización
✓Dominio de JavaScript y TypeScript
✓Experiencia avanzada con React y arquitectura basada en componentes
✓Habilidad comprobada en optimización de UIs con datos masivos (virtualización, memoización)
✓Experiencia sólida en pruebas automatizadas (unitarias, integración, E2E)

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ReactTypeScriptJavaScriptJestReact Testing LibraryPlaywrightCypressClickHouseTime-series dataLarge analytical backends

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About the Role Thousands of engineers sign in daily to inspect traces, update prompts, and run experiments on an open-source LLM engineering platform — think Datadog, but for AI observability. Full LLM inputs and outputs can span tens of thousands of tokens. Your job: make that experience fast and intuitive. You love profiling React renders. You know when to virtualize, memoize, or restructure state. The data is massive — the interface should never feel like it is. This is a high-ownership, senior-level role on a small, remote-first European engineering team with meaningful cross-functional collaboration. What You'll Do Build performant trace views — Own rendering of large LLM data: identify bottlenecks, optimize data loading, reduce re-renders so even the largest agent traces feel snappy. Own the React architecture — Shape how components are built, code is structured, and tests are written. Keep the codebase current with React Compiler and emerging patterns. Drive data visualization — Design and implement virtualized lists, grids, incremental loading, and data-heavy dashboards (cost, latency, evaluation results). Raise the quality bar — Champion automated testing across unit, integration, and end-to-end layers; conduct thorough code reviews and mentor peers. Collaborate cross-functionally — Work closely with product and backend engineers to ship features end-to-end across the full LLM development lifecycle. Benefits Salary: $90,000 – $160,000 USD annually Equity participation in a well-funded, high-growth AI infrastructure company Small team — high autonomy, high ownership, direct impact Remote-first with regular in-person collaboration in Berlin (~once per month) Location Remote (EU-based). The team is distributed across Germany, Austria, Switzerland, the UK, the Netherlands, France, Spain, Sweden, and Poland. You must be based in the EU with the right to work without sponsorship. Expect approximately one week per month on-site in Berlin, Germany . Visa sponsorship: Not available.

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