Senior Mobile Engineer (React + React Native)

Casado; Brazil; On-site; BRL 173,000 - 207,000; Full time

Job summary

Casado seeks a Senior Front-End Engineer (React + React Native) to own web and mobile product experiences. You will build, test, and optimize features across web and iOS/Android, guided by analytics and user behavior.

You will collaborate with leadership to ship impactful improvements in a fast-paced startup environment. The role emphasizes data-driven decisions, performance tuning, and close partnership with product.

Qualifications

• Fluent/Native English is required.
• 5+ years of experience with React.
• 5+ years of React Native experience.
• 5+ years of product analytics (frontend engineering).
• 4+ years JavaScript (ES6+).
• 4+ years Next.js experience.
• Strong React.js and Next.js experience including SSR/SSG and high-performance patterns.

Responsibilities

• Build and maintain high-quality web and mobile apps using React/Next.js and React Native.
• Deliver fast, smooth UI with optimized load times and navigation.
• Own app performance monitoring and product health using analytics.
• Investigate data-driven issues and propose data-backed improvements.
• Contribute to performance optimization, routing, and architecture as the product scales.
• Integrate REST and GraphQL APIs with effective state management and caching.
• Write automated tests for web and mobile features.

Skills

React

React Native

Product Analytics

JavaScript ES6+

Next.js

HTML5/CSS3

Tailwind CSS

Styled Components

REST APIs

GraphQL

Testing (Jest/RTL/Cypress)

Analytics tools (PostHog/Mixpanel/Ampt

English proficiency

TypeScript

Node.js

Tools

Tailwind CSS

Styled Components

Node.js

Job description

Senior Mobile Engineer (React + React Native)

International job opportunity!! R$ 17,000,00 como PJ ( US 3.3k ) Project Duration = 12_Plus

Required

• English – Fluent/Native
• 5+ Years React
• 5+ Years React Native
• 5+ Years Product Analytics (Frontend Engineering)
• 4+ Years JavaScript (ES6+)
• 4+ Years Next.js
• Strong experience with React.js and Next.js, including SSR, SSG, routing, and high-performance patterns.
• Solid experience developing mobile apps with React Native, including navigation, performance tuning, and familiarity with native modules.
• Strong command of JavaScript (ES6+) and asynchronous programming.
• Expertise in HTML5 and CSS3. Experience with utility or component-based systems like Tailwind or Styled Components.
• Experience integrating REST and GraphQL APIs with solid error handling, caching, and state management.
• Familiarity with modern testing frameworks such as Jest, React Testing Library, or Cypress.
• Experience working with product analytics tools (PostHog, Mixpanel, Amplitude, or similar); comfort analyzing funnels, events, retention, and session recordings.
• Ability to work effectively in fast-paced, iterative environments and thrive on shipping frequently.

Nice to Have

• Experience with TypeScript (interfaces, generics, type inference).
• Experience with Node.js (Express, NestJS) for backend collaboration.
• Experience in real estate, analytics, or data-driven consumer platforms.
• Experience taking a product feature from concept → release → production validation using analytics.
• Familiarity with mobile debugging tools and profiling performance across iOS and Android.

Description / Responsibilities

What They'll Do

• Build and maintain high-quality applications using React and Next.js for web, React Native for iOS and Android.
• Ship improvements quickly across both platforms, ensuring fast load times, smooth navigation, and polished user experience.
• Own performance monitoring and product health. Monitor app performance and user behavior using PostHog analytics; identify conversion bottlenecks, retention issues, and UX friction before they become problems.
• Diagnose product issues with data. When metrics drop or adoption is lower than expected, you'll investigate technical causes, UX problems, and funnel breakpoints—then recommend solutions backed by data.
• Work on performance optimization, SSG/SSR strategies, routing, component architecture, and best practices as the product scales.
• Integrate APIs effectively. Work with REST and GraphQL APIs with solid handling of state, caching, error recovery, and real-time updates.
• Contribute to product strategy by suggesting improvements based on user behavior, feature adoption rates, session recordings, and performance data.
• Participate actively in sprints: two-week cycles, daily standups, and regular check-ins with the CEO and team.
• Take ownership of "done." Features are complete when they're released, monitored in production, and validated to be working as expected through PostHog analytics and user behavior.
• Write and maintain automated tests to ensure reliability and maintainability across both web and mobile.

What We're Looking For

We are looking for a Senior Front-End Engineer with strong experience in React for web and solid hands-on expertise with React Native for iOS and Android. You won't just build features—you'll take ownership of the entire mobile product experience, from architecture and performance to user behavior and conversion strategy. You'll work closely with the CEO, Tech Lead, and a highly engaged engineering team to guide architectural decisions, deliver features that matter, and continuously improve stability and usability across web and mobile. You'll bring data-driven insights from analytics, diagnose product friction before users complain, and contribute strategic ideas on what to build next. This is a role where technical excellence meets product thinking.