Senior React Native Engineer

Scrambly; Poland; On-site; PLN 240,000 - 360,000; Full time

Benefits offered by this job

Growth culture

Ownership of features

Modern tech stack

Job summary

Scrambly is seeking a Senior React Native Engineer to own high-impact features for iOS and Android, with web work in Next.js. You will write performant TypeScript code, maintain app stability, and collaborate closely with Backend, QA, and Product teams to deliver a seamless user experience.

You will engage in architectural discussions, drive performance improvements, and help reduce technical debt while shaping the product’s technical direction with the mobile team lead and other seniors.

Qualifications

• 5+ years of software engineering with at least 4 years in React Native.
• Strong TypeScript and modern React patterns (Hooks).
• Deep understanding of iOS/Android build systems and native Swift/Kotlin.
• Experience with state management libraries like Redux Toolkit or Zustand.
• Testing: Jest and E2E testing (Maestro or Detox).
• Good English communication (written and spoken).
• Next.js experience is a plus.

Responsibilities

• Design & implement high-quality cross-platform apps using React Native and TypeScript.
• Build reusable UI components and performant lists; integrate backend via RESTful APIs and WebSockets.
• Ensure app stability; optimize performance; manage CI/CD pipelines for app releases.
• Collaborate with Backend, QA, and Product teams; participate in architectural discussions.

Skills

React Native

TypeScript

English

Communication

Tools

Redux Toolkit

Zustand

TanStack Query

Jest

Maestro

Detox

Next.js

Swift/Kotlin

Job description

About The Company

Scrambly is one of the fastest-growing adtech startups in the world, featured in the AppsFlyer Performance Index and Singular ROI Index in just 3.5 years. We’re growing 250%+ YoY across revenue, team, product, and technology — fully bootstrapped and profitable. We’re building the future of app discovery: a reward-powered alternative to the App Store and Google Play. Our loyalty-driven ecosystem connects millions of users with the world’s top apps and delivers unmatched, ROI-focused growth for mobile advertisers. Our mission is to build a true alternative to traditional app stores — fueled by rewards and data — and create a new, performance-first growth engine for mobile app advertisers.

About The Role

We are looking for an experienced Senior React Native Engineer to join the Scrambly mobile team and help build and scale our app for iOS and Android. In this role, you will take full ownership of complex, high-impact features for a high-traffic platform serving millions of users globally. You will also contribute to our web platform built on Next.js, making cross-platform versatility a key part of the role. Your primary focus will be on writing performant, well-architected TypeScript code within a modern React Native stack. You will play a key role in maintaining app stability, keeping the application fast, reliable, and easy to maintain. This position offers a direct opportunity to impact business metrics by reducing technical debt and driving performance improvements across the platform. Success in this role requires strong cross-functional collaboration. You will work directly with Backend, QA, and Product teams to clarify requirements, solve complex engineering challenges, and deliver a seamless UX. Additionally, you will actively contribute to architectural discussions, helping to shape the technical direction of the product alongside the mobile team lead and other senior engineers.

Key Responsibilities

Design & Implementation

You will develop high-quality, cross-platform apps using React Native and TypeScript, building reusable UI components and performant lists (e.g., FlashList) that match design specs. This includes integrating backend services via RESTful APIs and WebSockets, debugging platform-specific issues using Xcode and Android Studio, and writing or modifying native Swift/Kotlin modules as needed.

Engineering Standards & Quality

You will champion code quality by writing clean, testable TypeScript code and participating in peer reviews. Your role involves improving overall codebase health by resolving technical debt, expanding test coverage, and driving scalable architectural decisions regarding state management (e.g., Redux Toolkit, Zustand) and navigation.

Performance, Reliability & Collaboration

You will monitor app stability and resolve crashes using tools like Sentry or Crashlytics while optimizing frame rates, memory, and battery usage. Additionally, you will manage CI/CD pipelines for smooth App Store and Google Play releases and effectively translate technical constraints into viable solutions for non-technical stakeholders.

Requirements

• Experience: 5+ years of software engineering, with at least 4 years strictly focused on React Native.
• Core Tech Stack: Strong proficiency in TypeScript, modern React patterns (Hooks), and the React Native ecosystem (CLI, Hermes).
• Native Fundamentals: Deep understanding of iOS/Android build systems (Gradle, Pods, signing) and ability to read/write Swift/Kotlin for debugging.
• Architecture: Proven ability to make and defend scalable architecture decisions using state management libraries (Redux Toolkit, Zustand, or TanStack Query).
• Testing: Hands-on experience with unit/integration testing (Jest) and E2E testing (Maestro or Detox).
• Communication: Ability to clearly explain technical concepts to diverse teams.
• Language: Upper-Intermediate (B2) or higher English proficiency (written and spoken).
• Web: Next.js experience is a strong advantage, though a solid React foundation and willingness to learn is acceptable.

Nice to Have

• Experience launching and maintaining a B2C app with 100k+ Monthly Active Users (MAU)
• Hands-on experience writing Native Modules or JSI/TurboModules from scratch
• Familiarity with mobile analytics tools (Segment, Amplitude) and A/B testing implementation
• Experience with automation tools like Maestro or Appium
• Knowledge of backend fundamentals (Node.js) to debug API integrations effectively

What We Offer

• Scale & Impact: Your code will impact millions of users globally. Performance optimizations you implement will translate into immediate value and improved user experience
• Modern Stack: Work with the latest React Native tools and standards (TypeScript, Hermes, etc.) without being bogged down by legacy spaghetti code
• Growth Culture: A collaborative environment with rigorous code reviews and knowledge sharing — we value the best idea, regardless of title or seniority
• Ownership: A high level of ownership where you can see your features go live quickly in a fast-paced environment

By submitting this application, I agree that my personal data will be collected, processed, and retained by the company solely for the purposes of managing and assessing my candidacy.