Senior React & React Native Engineer (Web & Mobile)

Keylent Inc; Jacksonville (FL); Hybrid; USD 120,000 - 180,000; Full time

Job summary

Keylent Inc. seeks an experienced Senior React & React Native Developer to analyze, design, develop, and maintain business applications that support organizational needs.

This hybrid role in Jacksonville, FL focuses on building modern web and mobile applications, improving systems, and delivering secure, scalable software. You will work with REST/JSON APIs, implement i18n, support native mobile modules in Swift/Kotlin, and help deliver AI-enabled conversational UI features.

Qualifications

• 10 years of professional software development experience.
• Strong experience developing modern web applications using React.
• Strong experience developing mobile applications using React Native.
• Recent, hands-on experience building and delivering both web and mobile applications.
• Native mobile development experience with Swift and/or Kotlin, including React Native module development and platform integrations.
• Experience publishing applications to Apple App Store and Google Play Store.
• Strong understanding of OAuth 2.0 and OpenID Connect (OIDC).
• Experience implementing secure token storage and mobile application security hardening.
• Strong experience integrating REST APIs and working with JSON.
• Experience implementing internationalization (i18n) and localization.
• Experience building conversational or chat-based user interfaces, including LLM-integrated features and streaming responses.
• Ability to take ownership of existing applications, troubleshoot issues, and improve stability with limited knowledge transfer.

Responsibilities

• Analyze business information systems, applications, and tools to identify opportunities for improvement and implement solutions that meet organizational requirements.
• Assess business needs, technical feasibility, system performance, and potential risks to optimize application value and functionality.
• Design, develop, code, test, and maintain new and existing web and mobile applications.
• Build and deliver modern applications using React and React Native.
• Troubleshoot, stabilize, and enhance existing applications, including projects with limited documentation or knowledge transfer.
• Develop and maintain native mobile capabilities using Swift and/or Kotlin to support React Native modules and platform integrations.
• Integrate applications with REST/JSON APIs and implement secure authentication and authorization workflows.
• Develop conversational and chat-based user interfaces, including LLM-integrated experiences and streaming responses.
• Implement internationalization (i18n) and localization to support diverse users and markets.
• Coordinate software installations, provide ongoing technical support, and ensure application reliability.
• Conduct code and configuration audits to evaluate accuracy, security, and performance.
• Recommend and implement improvements to application design, system performance, productivity, and end-user experience.
• Develop and maintain technical documentation, including software user guides, maintenance procedures, and development best practices.
• Identify opportunities for process optimization and recommend improvements to policies, procedures, and system functionality.
• Collaborate with internal and external stakeholders to resolve application and business system issues.
• May provide indirect technical leadership to less experienced developers on smaller projects or components of larger initiatives.

Skills

React

React Native

JavaScript/TypeScript

OAuth 2.0 / OIDC

REST / JSON

i18n / localization

AI / conversational UI

Swift / Kotlin

App publishing (iOS/Android)

Security hardening

Ownership & troubleshooting

API integration

Job description

Keylent Inc. seeks an experienced Senior React & React Native Developer to analyze, design, develop, and maintain business applications that support organizational needs.

This hybrid role in Jacksonville, FL focuses on building modern web and mobile applications, improving systems, and delivering secure, scalable software. You will work with REST/JSON APIs, implement i18n, support native mobile modules in Swift/Kotlin, and help deliver AI-enabled conversational UI features.