Mid/Senior Frontend Developer

Location: Krakow, Poland Workplace: Remote Sensor Tower’s digital intelligence platform provides unparalleled insight into market trends, advertising, competitor’s strategies, and consumer/user audience across mobile, web, and gaming. Sensor Tower’s insights are trusted by more than 2,500 enterprises worldwide across tech, retail/commerce, entertainment/media, gaming, consumer packaged goods and finance. Role Summary: As a Frontend Engineer at Sensor Tower, you will not only build features, you will define how we build them. You will take ownership of major technical components, ensuring our applications are scalable, maintainable, and fast. In our lean and flat organization, your voice will shape the technical direction of our product, helping us deliver an intuitive, fluid user experience that helps our customers understand the digital ecosystem.   Fulfill your potential with us: - Architect and deliver complex, scalable frontend systems that are simple and effective, removing unnecessary complexity from our codebase. - You will partner with Product Managers to co-author requirements and shape the scope, ensuring engineering feasibility is considered during ideation, not just execution. - Lead technical decision-making for medium-to-large scoped features, taking responsibility for the successful delivery of value to the customer, not just the completion of tickets. - Mentor junior and mid-level engineers through code reviews, pair programming, and by instilling quality-first habits across the team. - Take ownership of the frontend stack by proactively identifying bottlenecks, technical debt, or systemic issues and driving the initiatives to fix them. - Advocate for and drive best practices in React, TypeScript, and web performance optimization across the engineering organization. - Collaborate deeply with Data Science and Backend Engineers to ensure seamless data flow and end-to-end system reliability, and use these partnerships to progressively expand your expertise across the full stack.   What we are interested in:   - 4+ years of software engineering experience with a deep specialization in modern JavaScript, TypeScript, and React. - Proven ability to architect complex state management. While our stack relies on TanStack Query, React Router and Zustand, we value engineers who understand the principles and can adapt expertise from other libraries like Redux, MobX, NextJS. - You can design systems that handle complexity without becoming complicated, prioritizing long-term maintainability. - Experience elevating the skills of peers. You don't just review their code; you teach patterns and best practices. - Competence in writing robust and efficient unit and integration tests using frameworks like Jest or Playwright. - Deep understanding of web performance, browser internals, and optimization techniques for data-heavy applications. - A "Product Owner" mindset. You care deeply about the "why" behind every feature, viewing code as a tool to solve real user problems. You are comfortable pushing back on requirements and proposing alternative solutions that drive better business outcomes and user experiences.   Extra Credit:   - Experience in data visualization and analytics (handling large datasets, heavy DOM manipulation with libraries like Highcharts). - A portfolio, GitHub history, or technical writing that demonstrates clean code, an eye for design, and the ability to solve complex architectural challenges. - Familiarity with back end frameworks Ruby on Rails/Angular and different types of DBs (Clickhouse, Mongo, Postgres) - Knowledge of AI-driven coding tools and models as we encourage leveraging AI to enhance coding efficiency and unlock creative potential   Blog Posts Read more about some of our Technical challenges here (written by members of our engineering team): https://sensortower.com/blog/how-we-scaled-to-thousands-of-sidekiq-workers     About Sensor Tower Sensor Tower is a global provider of digital intelligence solutions, empowering companies to understand consumer behavior and market performance across mobile apps, digital platforms, and gaming ecosystems. Headquartered in San Francisco, Sensor Tower's insights are trusted by more than 2,500 enterprises worldwide.   Founded in 2013, Sensor Tower’s market insights have helped marketers, app developers, and gaming leaders demystify the mobile app ecosystem with visibility into usage, engagement, and paid acquisition strategies. Today, Sensor Tower’s digital market insights platform has expanded to include Gaming, Web, Audience, and Digital Advertising Insights, helping global leaders understand market trends and their competitor’s strategies and audiences across the entire digital ecosystem.   Why Sensor Tower? Our flexible work environment allows employees to live in greater connection with the people, places, and activities they love! Global Teams Sensor Tower has a global presence, with teams across the world and available in most time zones, including North America, Europe, Middle East, Africa, APAC and LATAM. We maintain regional offices in SF, LA, NY, London, Singapore, Beijing, Seoul, Tokyo and Vancouver.   We are committed to equal employment opportunities regardless of race, color, ancestry, religion, sex, national origin, sexual orientation, age, citizenship, marital status, disability, gender identity, and veteran status. We will consider qualified applicants with arrest and conviction records. If you have a disability or special need, please do not hesitate to let us know and we'll do our best to accommodate.   Fraud warning: It's common for scammers to create positions that look legitimate on other sites. To ensure your submission is considered, only apply for positions at Sensor Tower through our company website or through posts directly associated with Sensor Tower company profiles on sites such as LinkedIn, Indeed, BuiltIn or Hackajob. At no point will Sensor Tower ever ask for money, credit card, or bank account information to complete a job application. Communications received from Sensor Tower are only sent by e-mail addresses ending in sensortower.com http://sensortower.com. All Sensor Tower interviews will be conducted via phone or Zoom. At no time will a conversation be moved to an alternative email outside of sensortower.com http://sensortower.com or text. Should an issue arise that you feel we should be aware of, please contact us. Please provide your resume when applying. To all recruitment agencies: Sensor Tower does not accept third party resumes. Please do not send resumes to our jobs alias, Sensor Tower employees or any other organization location. Sensor Tower is not responsible for any fees related to unsolicited resumes. Sensor Tower will not pay any third-party agency or company that does not have a signed agreement with Sensor Tower. We may use artificial intelligence (AI) tools to support parts of the hiring process, such as reviewing applications, analyzing resumes, or assessing responses. These tools assist our recruitment team but do not replace human judgment. Final hiring decisions are ultimately made by humans. If you would like more information about how your data is processed, please contact us.