Mobile Developer (Swift and React Native)
99x Brazil (formerly Nextly) • São Paulo, State of São Paulo, Brazil
Posted: July 8, 2026
Job Description
We're hiring a mobile developer to help our client scale. As one of three founding engineers on a new team, you'll develop features end-to-end, own the app's architecture, and shape the decisions that drive our growth. You'll touch every part of the stack and ship from day one.
Tech stack: iOS and Android apps built natively in Swift and Kotlin plus React Native, with an Elixir backend.
Responsibilities
- Produce fully functional mobile applications writing clean code
- Gather specific requirements and suggest solutions
- Troubleshoot and debug to optimize performance
- Design interfaces to improve user experience
- Liaise with Product development team to plan new features
- Ensure new and legacy applications meet quality standards
- Research and suggest new mobile products, applications and protocols
- Advanced/Business English speaking and writing skills;
- 6+ years of experience in mobile application development
- Experience owning mobile application architecture and contributing to senior technical decision-making in a scaling product environment
- Proficient in native iOS development (Swift), native Android development (Kotlin), and React Native
- Experience with SwiftUI and UIKit
- Experience with composable architecture
- Experience working with Elixir in production environments
- Experience with consumer mobile applications
- Experience collaborating closely with product, designers, and other engineers, and helping shape technical decisions with leadership
- Available to work mostly during Brazil time zone business hours
- Experience with SaaS products is a plus.
- BSc degree in Computer Science or relevant field is a plus.
Additional Content
We're hiring a mobile developer to help our client scale. As one of three founding engineers on a new team, you'll develop features end-to-end, own the app's architecture, and shape the decisions that drive our growth. You'll touch every part of the stack and ship from day one.
Tech stack: iOS and Android apps built natively in Swift and Kotlin plus React Native, with an Elixir backend.
Responsibilities
- Produce fully functional mobile applications writing clean code
- Gather specific requirements and suggest solutions
- Troubleshoot and debug to optimize performance
- Design interfaces to improve user experience
- Liaise with Product development team to plan new features
- Ensure new and legacy applications meet quality standards
- Research and suggest new mobile products, applications and protocols
- Advanced/Business English speaking and writing skills;
- 6+ years of experience in mobile application development
- Experience owning mobile application architecture and contributing to senior technical decision-making in a scaling product environment
- Proficient in native iOS development (Swift), native Android development (Kotlin), and React Native
- Experience with SwiftUI and UIKit
- Experience with composable architecture
- Experience working with Elixir in production environments
- Experience with consumer mobile applications
- Experience collaborating closely with product, designers, and other engineers, and helping shape technical decisions with leadership
- Available to work mostly during Brazil time zone business hours
- Experience with SaaS products is a plus.
- BSc degree in Computer Science or relevant field is a plus.