I'm Samuel Karanja, a Senior Mobile Engineer focused on Android with 9+ years of experience delivering fast, secure, scalable mobile apps. I specialize in Kotlin, Jetpack Compose, MVVM, and Clean Architecture, and I leverage modern DevOps practices to ship high-quality solutions across fintech, e-commerce, and real estate domains. I enjoy turning complex requirements into robust, maintainable mobile experiences and mentoring teammates to grow their engineering skills. I thrive in cross-functional environments, value clean code and continuous learning, and I’m comfortable with REST APIs, offline-first design, CI/CD, and end-to-end app lifecycle management. I continuously explore new technologies to keep apps production-ready and reliable, while focusing on performance, security, and great user experiences.

Samuel Karanja

I'm Samuel Karanja, a Senior Mobile Engineer focused on Android with 9+ years of experience delivering fast, secure, scalable mobile apps. I specialize in Kotlin, Jetpack Compose, MVVM, and Clean Architecture, and I leverage modern DevOps practices to ship high-quality solutions across fintech, e-commerce, and real estate domains. I enjoy turning complex requirements into robust, maintainable mobile experiences and mentoring teammates to grow their engineering skills. I thrive in cross-functional environments, value clean code and continuous learning, and I’m comfortable with REST APIs, offline-first design, CI/CD, and end-to-end app lifecycle management. I continuously explore new technologies to keep apps production-ready and reliable, while focusing on performance, security, and great user experiences.

Available to hire

I’m Samuel Karanja, a Senior Mobile Engineer focused on Android with 9+ years of experience delivering fast, secure, scalable mobile apps. I specialize in Kotlin, Jetpack Compose, MVVM, and Clean Architecture, and I leverage modern DevOps practices to ship high-quality solutions across fintech, e-commerce, and real estate domains. I enjoy turning complex requirements into robust, maintainable mobile experiences and mentoring teammates to grow their engineering skills.

I thrive in cross-functional environments, value clean code and continuous learning, and I’m comfortable with REST APIs, offline-first design, CI/CD, and end-to-end app lifecycle management. I continuously explore new technologies to keep apps production-ready and reliable, while focusing on performance, security, and great user experiences.

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Experience Level

Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Intermediate
Intermediate
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Language

English
Fluent
Swahili
Fluent

Work Experience

Senior Mobile Engineer at Kanalight Kenya
June 1, 2025 - September 25, 2025
Developed a high-performance eCommerce app using Flutter (Dart), implementing BLoC, GetX, and Provider for state management. Integrated RESTful APIs and Isar DB for offline-first functionality, ensuring seamless user experience. Optimized CI/CD pipelines for automated testing and deployment, improving release efficiency. Mentored junior developers in Flutter best practices and clean architecture.
Senior Android Engineer at Andela — Remote (Client: Banque Misr, Egypt)
December 31, 2023 - September 25, 2025
Led development of a secure internal Android app for loan officers using Kotlin and Jetpack Compose. Designed app using MVVM architecture, implementing reusable UI components and smooth navigation flows. Applied encryption and secure offline storage to ensure data integrity and app functionality in low-connectivity environments. Integrated RESTful APIs with Retrofit & Coroutines, optimizing performance and error handling. Conducted A/B testing, user feedback sessions, and analytics integration to guide feature improvements. Led code reviews and architecture planning, mentoring junior engineers on Compose and performance optimization.
Android Engineer at Andela — Remote (Client: Homie, USA)
July 31, 2022 - September 25, 2025
Designed and implemented core features using Kotlin boosting user engagement and revenue by over 50%. Leveraged Dagger and Hilt for dependency injection and asynchronous data handling using Kotlin Coroutines. Spearheaded the migration of legacy code to Android Architecture Components, significantly improving maintainability and scalability. Mentored junior developers, ensuring adherence to coding standards and best practices. Worked in Agile sprints using Jira and Slack, ensuring timely delivery of features. Collaborated closely with cross-functional teams to ensure seamless feature integration, enhancing app reliability and performance.
Android Engineer at Savlon Africa
January 1, 2019 - September 25, 2025
Led the development and deployment of financial apps leveraging Android Architecture Components and Retrofit for RESTful API integrations. Led technical decision-making processes, aligning app features with business goals and user needs. Integrated analytics tools to measure user engagement and drive data-informed improvements. Mentored junior Android developers, fostering their growth and development within the team. Delivered integrated app solutions that reduced operational costs and increased revenue for clients by optimizing workflows and data processing efficiency.
Software Engineer at Toprank Technologies
December 31, 2017 - September 25, 2025
Developed a dynamic e-commerce Android application using Java. Improved application stability and performance through rigorous testing and debugging. Implemented cloud support with Google Cloud and Firebase, enabling scalable backend services. Created custom views and animations for improved user experience.
Senior Mobile Engineer at Kanalight Kenya
June 1, 2025 - September 25, 2025
Developed a high-performance eCommerce app using Flutter (Dart), implementing BLoC, GetX, and Provider for state management. Integrated RESTful APIs and Isar DB for offline-first functionality, ensuring seamless user experience. Optimized CI/CD pipelines for automated testing and deployment, improving release efficiency. Mentored junior developers in Flutter best practices and clean architecture.
Senior Android Engineer at Andela
December 1, 2023 - September 25, 2025
Led development of a secure internal Android app for loan officers using Kotlin and Jetpack Compose. Designed app using MVVM architecture, implementing reusable UI components and smooth navigation flows. Applied encryption and secure offline storage to ensure data integrity and app functionality in low-connectivity environments. Integrated RESTful APIs with Retrofit & Coroutines, optimizing performance and error handling. Conducted A/B testing, user feedback sessions, and analytics integration to guide feature improvements. Led code reviews and architecture planning, mentoring junior engineers on Compose and performance optimization.
Android Engineer at Andela - Remote
July 1, 2022 - September 25, 2025
Designed and implemented core features using Kotlin boosting user engagement and revenue by over 50%. Leveraged Dagger and Hilt for dependency injection and asynchronous data handling using Kotlin Coroutines. Spearheaded the migration of legacy code to Android Architecture Components, significantly improving maintainability and scalability. Mentored junior developers, ensuring adherence to coding standards and best practices. Worked in Agile sprints using Jira and Slack, ensuring timely delivery of features. Collaborated closely with cross-functional teams to ensure seamless feature integration, enhancing app reliability and performance.
Android Engineer at Salvon Africa
January 1, 2019 - September 25, 2025
Led the development and deployment of financial apps leveraging Android Architecture Components and Retrofit for RESTful API integrations. Led technical decision-making processes, aligning app features with business goals and user needs. Integrated analytics tools to measure user engagement and drive data-informed improvements. Offered mentorship to junior Android developers, fostering their growth and development within the team. Delivered integrated app solutions that reduced operational costs and increased revenue for clients by optimizing workflows and data processing efficiency.
Software Engineer at Toprank Technologies
January 1, 2017 - September 25, 2025
Developed a dynamic e-commerce Android application using Java. Improved application stability and performance through rigorous testing and debugging. Implemented cloud support with Google Cloud and Firebase, enabling scalable backend services. Created custom views and animations for improved user experience.
Senior Mobile Engineer at Kanalight
June 1, 2025 - September 25, 2025
Developed a high-performance eCommerce app using Flutter (Dart), implementing BLoC, GetX, and Provider for state management. Integrated RESTful APIs and Isar DB for offline-first functionality, ensuring seamless user experience. Optimized CI/CD pipelines for automated testing/deployment, improving release efficiency. Mentored junior developers in Flutter best practices and clean architecture.
Android Engineer at Andela
December 31, 2023 - September 25, 2025
Led development of a secure internal Android app for loan officers using Kotlin and Jetpack Compose. Designed app using MVVM, implementing reusable UI components and smooth navigation flows. Applied encryption and secure offline storage to ensure data integrity and app functionality in low-connectivity environments. Integrated RESTful APIs with Retrofit & Coroutines, optimizing performance and error handling. Conducted A/B testing, user feedback sessions, and analytics integration to guide feature improvements. Led code reviews and architecture planning, mentoring junior engineers on Compose and performance optimization.
Android Engineer at Andela - Remote (Client: Homie, USA)
July 1, 2022 - September 25, 2025
Designed and implemented core features using Kotlin boosting user engagement and revenue by over 50%. Leveraged Dagger and Hilt for dependency injection and asynchronous data handling using Kotlin Coroutines. Spearheaded the migration of legacy code to Android Architecture Components, significantly improving maintainability and scalability. Mentored junior developers, ensuring adherence to coding standards and best practices. Worked in Agile sprints using Jira and Slack, ensuring timely delivery of features. Collaborated with cross-functional teams to ensure seamless feature integration, enhancing app reliability and performance.
Android Engineer at Salvon Africa
December 31, 2019 - September 25, 2025
Led the development of financial apps leveraging Android Architecture Components and Retrofit for RESTful API integrations. Led technical decision-making processes, aligning app features with business goals and user needs. Integrated analytics tools to measure user engagement and drive data-informed improvements. Mentored junior Android developers, fostering growth and development within the team. Delivered integrated app solutions that reduced operational costs and increased revenue by optimizing workflows and data processing.
Software Engineer at Toprank Technologies
December 31, 2017 - September 25, 2025
Developed a dynamic e-commerce Android application using Java. Improved application stability and performance through rigorous testing and debugging. Implemented cloud support with Google Cloud and Firebase, enabling scalable backend services. Created custom views and animations for improved user experience.
Senior Mobile Engineer at Kanalight Kenya
June 1, 2025 - September 25, 2025
Developed a high-performance eCommerce app using Flutter (Dart), implementing BLoC, GetX, and Provider for state management. Integrated RESTful APIs and Isar DB for offline-first functionality, ensuring seamless user experience. Optimized CI/CD pipelines for automated testing/deployment, improving release efficiency. Mentored junior developers in Flutter best practices and clean architecture.
Senior Android Engineer at Andela
December 1, 2023 - September 25, 2025
Led development of a secure internal Android app for loan officers using Kotlin and Jetpack Compose. Designed app using MVVM, implementing reusable UI components and smooth navigation flows. Applied encryption and secure offline storage to ensure data integrity and app functionality in low-connectivity environments. Integrated RESTful APIs with Retrofit & Coroutines, optimizing performance and error handling. Conducted A/B testing, user feedback sessions, and analytics integration to guide feature improvements. Led code reviews and architecture planning, mentoring junior engineers on Compose and performance optimization.
Android Engineer at Andela - Remote
July 1, 2022 - September 25, 2025
Designed and implemented core features using Kotlin boosting user engagement and revenue by over 50%. Leveraged Dagger and Hilt for dependency injection and asynchronous data handling using Kotlin Coroutines. Spearheaded the migration of legacy code to Android Architecture Components, significantly improving maintainability and scalability. Mentored junior developers, ensuring adherence to coding standards and best practices. Worked in Agile sprints using Jira and Slack, ensuring timely delivery of features. Collaborated closely with cross-functional teams to ensure seamless feature integration, enhancing app reliability and performance.
Android Engineer at Salvon Africa
January 1, 2019 - September 25, 2025
Led the development and deployment of financial apps leveraging Android Architecture Components and Retrofit for RESTful API integrations. Led technical decision-making, aligning app features with business goals and user needs. Integrated analytics tools to measure user engagement and drive data-informed improvements. Offered mentorship to junior Android developers, fostering their growth and development within the team. Delivered integrated app solutions that reduced operational costs and increased revenue by optimizing workflows and data processing.
Software Engineer at Top Rank Technologies
January 1, 2017 - September 25, 2025
Developed a dynamic e-commerce Android application using Java. Improved application stability and performance through rigorous testing and debugging. Implemented cloud support with Google Cloud and Firebase, enabling scalable backend services. Created custom views and animations for improved user experience.

Education

Bachelor of Computer Science at St Paul University
January 1, 2015 - November 18, 2022
Computer Science at St Paul University
January 1, 2013 - January 1, 2022
Computer Science at St Paul University
January 1, 2013 - January 1, 2022
Computer Science at St Paul University
January 1, 2013 - January 1, 2022
Computer Science at St Paul University
January 1, 2013 - January 1, 2022

Qualifications

ALC Certificate
May 9, 2018 - August 22, 2018
Google Associate Android Developer (AAD)
January 11, 2030 - September 25, 2025
Google Associate Android Developer (AAD)
January 11, 2030 - September 25, 2025
Google Associate Android Developer (AAD)
January 11, 2030 - September 25, 2025
Google Associate Android Developer (AAD)
January 11, 2030 - September 25, 2025

Industry Experience

Financial Services, Real Estate & Construction, Transportation & Logistics, Software & Internet, Agriculture & Mining, Consumer Goods, Professional Services, Retail, Media & Entertainment
    paper Homie Android App - Utah, USA

    During my time at Homie, one of Andela’s partners, I played a crucial role in developing the company’s Android application. This app revolutionized the home buying and selling process by seamlessly integrating experienced local real estate professionals with cutting-edge technology.

    Key Contributions:

    Feature Development: Led the design and implementation of key features that enhanced user experience and engagement. Collaborated closely with marketing and design teams to identify opportunities for improvement, resulting in an increase in user engagement and a significant boost in revenue.

    Cross-Functional Collaboration: Fostered strong partnerships with various teams to ensure alignment on business goals. This collaborative approach allowed for the rapid iteration of features based on user feedback and market trends.

    Mentorship and Code Reviews: Conducted thorough code reviews and provided mentorship to junior engineers, ensuring adherence to coding standards and best practices. This initiative not only improved code quality but also accelerated the onboarding process for new team members.

    Impact on Business Outcomes: Directly contributed to increased user traffic and enhanced sales of homes through the application. By implementing data-driven enhancements, I helped the team achieve a rise in transactions facilitated through the app.

    Through these efforts, I significantly advanced Homie’s mission to make homeownership more accessible, demonstrating a strong commitment to leveraging technology to drive meaningful change in the real estate industry.

    paper Banque(Bank) Misr Android App - Cairo,Egypt

    I utilized my expertise to help Banque Misr in creating their internal mobile app for use by loan officers.

    Some of my main contributions were:

    Built the main functions of the mobile app to ensure strong performance and reliability in real-world situations, which streamlined the loan processing workflow.
    Provided technical leadership by conducting thorough code reviews for a team of mobile engineers, offering helpful feedback and promoting a culture of continuous improvement. This guidance resulted in better code quality and fewer bugs during testing.
    Collaborated closely with cross-functional teams, such as backend developers and UX designers, to integrate RESTful APIs and create a unified application architecture.
    Through these efforts and others, I significantly improved the operational efficiency of loan officers, demonstrating a dedication to using technology to create meaningful solutions in the banking sector.