Mid/Senior Frontend Developer
Sensor Tower1 month ago
Kraków, PolandMid Level / Senior
Responsibilities
- Architect and deliver complex, scalable frontend systems with an emphasis on simplicity, maintainability, and performance.
- Partner with Product Managers to define requirements and scope features with engineering feasibility in mind.
- Lead technical decisions and successful delivery for medium-to-large scoped features.
- Mentor junior and mid-level engineers through code reviews, pair programming, and teaching best practices.
- Own the frontend stack by identifying and resolving bottlenecks, technical debt, and systemic issues.
- Drive best practices in React, TypeScript, web performance optimization, and quality-focused engineering.
- Collaborate with Data Science and Backend Engineers to support seamless data flow and end-to-end reliability.
Requirements
- 4+ years of software engineering experience with deep specialization in modern JavaScript, TypeScript, and React.
- Ability to architect complex state-management systems and adapt principles across libraries such as TanStack Query, React Router, Zustand, Redux, MobX, and NextJS.
- Experience designing complex systems that remain maintainable and understandable over time.
- Demonstrated ability to elevate peers through code reviews, mentoring, and teaching engineering patterns.
- Experience writing robust and efficient unit and integration tests using tools such as Jest or Playwright.
- Deep understanding of web performance, browser internals, and optimization for data-heavy applications.
- Product-oriented mindset with the ability to challenge requirements and propose solutions that improve user and business outcomes.
- Preferred experience with data visualization, large datasets, DOM-heavy applications, and libraries such as Highcharts.
- Preferred portfolio, GitHub history, or technical writing demonstrating clean code, design awareness, and complex architectural problem-solving.
- Familiarity with Ruby on Rails, Angular, ClickHouse, MongoDB, or PostgreSQL is a plus.
- Knowledge of AI-driven coding tools and models is considered valuable.
Benefits
- Flexible work environment allowing employees to live in greater connection with their people, places, and activities.
- Global team presence across North America, Europe, the Middle East, Africa, APAC, and LATAM, with regional offices in San Francisco, Los Angeles, New York, London, Singapore, Beijing, Seoul, Tokyo, and Vancouver.
Tech Stack
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