Senior Principal Software Engineer

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As a Senior Principal Engineer - React Native in the Client Foundations team, you will support our technical vision and strategy for the architecture that powers our Android, iOS and Web applications for 50M+ active customers. This team is the backbone of our customers’ experience, responsible for developing and maintaining best‑in‑class, high‑performing platform infrastructure for Android and iOS, including our underlying Rendering Engine framework.

We empower developers with robust tooling, ensure smooth production operations, and establish the testing best practices that keep the Zalando Fashion Store running at scale.

This is a pivotal role in Zalando’s strategic migration to React Native. You will jump into the most complex engineering challenges to ensure our transition is scalable, secure, and built for the future. We are looking for an experienced Principal Engineer with deep architectural fluency in the new React Native architecture and a proven ability to debug the entire stack, from React component re‑renders down to specific C++ bindings or native module layers.

Beyond the code, you will spearhead a culture of performance optimization and operational excellence. You will partner with product leaders and engineering teams to deliver foundational capabilities, while ensuring our mobile apps remain fluid and responsive. As a technical mentor, you will guide experienced engineers through complex profiling techniques and set the standards for UI performance metrics, ensuring that our technology landscape remains a benchmark for the industry.

At Zalando, our vision is to be inclusive by design. We do not discriminate on the basis of gender identity, sexual orientation, personal expression, ethnicity, religious belief, or disability status. You are welcome to leave out your picture, age, or marital status from your application. We only assess candidates on their qualifications and merit. We want to provide you with a great candidate experience.

Feel free to inform us of any accommodations you may need, so we can best support you throughout the hiring process.

• Solve the most complex engineering challenges in Zalando’s React Native migration; play a pivotal role in our strategic journey to React Native.
• Diagnose critical bottlenecks across the entire stack, from React re‑renders to C++ JSI or native modules.
• Utilize Xcode Instruments and Android Studio Profilers to fix blocked JavaScript threads, main thread bottlenecks, and native memory leaks.
• Champion a performance‑first culture by establishing and leading performance budgets, integrating monitoring into CI/CD pipelines, and spearheading internal training.
• Deliver best‑in‑class UI experiences, architect core app features and animations with performance as a primary consideration.
• Mentor experienced engineers on complex performance, profiling, and debugging techniques.

• Extensive experience developing large‑scale React Native applications with deep architectural fluency (Fabric, Turbo Modules, JSI).
• Full‑stack profiling capabilities, debugging from React component re‑renders to specific C++ JSI bindings or native modules in Swift/Objective‑C and Kotlin/Java.
• Expert‑level proficiency with native tooling, specifically Xcode Instruments and Android Studio Profilers.
• Advanced JS profiling experience using React Native Dev Tools and the Memory tab.
• Performance‑first design mindset and experience optimizing feature‑rich user interfaces.
• History of establishing a culture of performance optimization, including setting performance budgets and integrating monitoring into CI/CD.
• Strategic communication and mentoring skills, able to explain architectural trade‑offs to both technical and non‑technical stakeholders.

• Employee shares program
• 40% off fashion and beauty products sold and shipped by Zalando, 30% off Lounge by Zalando, discounts from external partners
• 2 paid volunteering days per year
• Hybrid working model up to 60% remote per week; actual practice depends on team collaboration needs
• Work from abroad for up to 30 working days a year
• 27 days of vacation per year for full‑time employees
• Relocation assistance available (subject to prior agreement)
• Family services, including counseling and support
• Health and wellbeing options (including Wellhub, formerly Gympass)
• Mental health support and coaching available
• Training platform and biannual peer‑to‑peer reviews to drive development

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