Available to hire
I’m Kristijan Bošnjak, a Senior Frontend Developer and Full Stack Engineer with 10+ years of experience building high-performance web and mobile applications. I’ve worked across fintech, healthcare analytics, ag-tech, iGaming, and identity verification, often taking full ownership of projects—from choosing the right architecture and tooling to shipping production-ready releases.
What I enjoy most is turning complex requirements into clean, scalable user experiences. I specialize in modern frontend engineering with React and TypeScript, and I’ve led teams and also built products solo, including real-time dashboards, data-heavy interfaces, reusable component libraries, and mobile apps deployed to both the App Store and Google Play. I’m currently focused on leading frontend architecture for an ag-tech platform and integrating AI-powered features into practical enterprise workflows.
Skills
Experience Level
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Intermediate
Intermediate
Language
English
Fluent
Croatian
Fluent
German
Intermediate
Work Experience
Senior Frontend Developer at Kepper Solutions
September 1, 2025 - PresentArchitected and built an ag-tech platform from the ground up, including technology selection, project structure, coding standards, and CI/CD setup. Developed core product features such as real-time data dashboards, complex data entry flows, and reporting modules for agricultural management workflows. Led internal AI tooling efforts by integrating LLM-powered features into enterprise workflows and collaborated with stakeholders to translate business needs into scalable frontend solutions.
Lead Frontend Developer at Finbalance GMBH
July 1, 2025 - September 3, 2025Led frontend architecture design and implementation for a high-performance React.js document digitization platform. Established core state management patterns using Zustand and React Query for efficient data fetching. Managed and mentored two frontend developers, coordinated team efforts, and ensured high code quality standards across development phases. Collaborated closely with backend teams to define API requirements ensuring seamless frontend-backend integration. Spearheaded rapid development cycles delivering significant platform features within tight timelines. Engineered reusable component libraries that accelerated team velocity by 40% while maintaining consistent UI/UX standards. Implemented comprehensive testing strategies using React Testing Library and Jest to ensure code reliability and reduce production bugs. Applied modern frontend architecture principles that improved application performance, maintainability, and overall developer experience.
Lead Frontend Developer at Finbalance GmbH
July 1, 2025 - September 3, 2025Led frontend architecture design and implementation of a high-performance React.js application including core patterns using Zustand for state management and React Query for efficient data fetching. Managed and mentored two frontend developers, coordinated team efforts, and ensured code quality standards across all development phases. Collaborated directly with backend teams to define API requirements for seamless frontend-backend integration. Spearheaded rapid development cycles delivering significant platform features within tight deadlines. Engineered reusable component libraries, accelerating team velocity by 40% while maintaining consistent UI/UX standards. Implemented comprehensive testing strategies using React Testing Library and Jest to ensure code reliability and reduce production bugs. Applied modern frontend architectural principles improving application performance, maintainability, and overall developer experience.
Lead Frontend Developer at Finbalance GmbH
September 1, 2024 - PresentLed frontend architecture design and implementation for a high-performance React.js application, establishing core patterns using Zustand for state management and React Query for efficient data fetching. Managed and mentored two frontend developers, coordinated team efforts and ensured code quality standards throughout all phases. Collaborated with the backend team to define API requirements and ensure seamless frontend-backend integration. Spearheaded rapid development cycles delivering significant platform features within tight timelines of a few months. Engineered reusable component libraries accelerating team velocity by 40% while maintaining consistent UI/UX standards. Implemented comprehensive testing strategies with React Testing Library and Jest to ensure code reliability and reduce production bugs. Applied modern frontend architecture principles that improved application performance, maintainability, and overall developer experience.
Lead Frontend Developer at Finbalance
September 1, 2024 - November 27, 2024Led frontend architecture design and implementation for a high-performance React application, establishing core patterns using Zustand for state management and React Query for efficient data fetching. Spearheaded rapid development cycles that delivered significant platform features in just a few months. Engineered reusable component libraries that accelerated team velocity while maintaining consistent UI/UX standards across the application. Implemented modern frontend architecture principles that improved application performance, maintainability, and developer experience.
Lead Frontend Developer at Finbalance
September 1, 2024 - June 12, 2024Led frontend architecture design and implementation for a high-performance React application, establishing core patterns using Zustand for state management and React Query for efficient data fetching. Spearheaded rapid development cycles delivering significant platform features within months. Engineered reusable component libraries accelerating team velocity while maintaining consistent UI/UX standards. Implemented modern frontend architecture principles improving application performance, maintainability, and developer experience.
Senior Frontend Developer at Medeanalytics
June 30, 2024 - September 3, 2025Developed robust analytics modules for a US healthcare sector project using React.js and Blueprint.js, handling complex data visualization and reporting requirements. Delivered enterprise-grade code quality by implementing comprehensive unit testing coverage for all components, ensuring 90%+ test coverage and production stability. Customized and optimized Blueprint.js components to meet specific healthcare industry UX requirements, improving user workflow efficiency and data accessibility.
Senior Frontend Developer at Medeanalytics
June 1, 2024 - September 3, 2025Developed robust analytics modules for a US healthcare sector project using React.js and Blueprint.js, managing complex data visualization and reporting requirements. Delivered enterprise-grade code quality by implementing comprehensive unit testing coverage for all components, ensuring 90%+ test coverage and production stability. Customized and optimized Blueprint.js components to meet specific healthcare industry UX requirements, improving user workflow efficiency and data accessibility.
Senior Frontend Developer at Medeanalytics
June 1, 2024 - September 3, 2025Developed robust analytics modules for a US healthcare sector project using React.js and Blueprint.js for complex data visualization and reporting. Delivered enterprise-grade code quality with over 90% unit testing coverage ensuring production stability. Customized and optimized Blueprint.js components to meet specific healthcare industry UX requirements improving user workflow efficiency and data accessibility.
Senior Frontend Developer at MedAnalytics
October 1, 2023 - June 30, 2024Developed new modules for a large-scale analytics platform serving the US healthcare sector using React.js and Blueprint.js. Delivered reliable, production-quality components with comprehensive unit test coverage, supporting complex, data-heavy user interfaces.
Senior Frontend Developer at MedeAnalytics
October 1, 2023 - June 30, 2024Worked on a large-scale analytics project for the US healthcare sector, utilizing React.js and Blueprint.js to develop robust new modules. Delivered high-quality code by creating comprehensive unit tests for every component. Expertly implemented and customized Blueprint.js components to enhance user experience.
Senior Frontend Developer at Medeanalytics
October 1, 2023 - June 1, 2024Worked on a large-scale analytics project for the US healthcare sector, utilizing React.js and Blueprint.js to develop robust new modules. Delivered high-quality code by creating comprehensive unit tests. Expertly implemented and customized Blueprint.js components to enhance user experience.
Senior Frontend Developer at Amygdala LTD
June 30, 2023 - September 3, 2025Architected and developed a real-time identification platform with React.js, Redux, Material UI, and Socket.io, delivering secure and responsive user authentication experiences. Delivered pixel-perfect UI implementations translating complex design requirements into production-ready features while maintaining 99% design fidelity. Built real-time communication features using Socket.io for instant identity verification feedback, enhancing user experience with live status updates and notifications. Collaborated with product and design teams to implement innovative identification workflows that improved client conversion rates and user satisfaction.
Senior Frontend Developer at Amygdala LTD
June 1, 2023 - September 3, 2025Architected and developed a real-time identification platform using React.js, Redux, Material UI, and Socket.io delivering secure and responsive user authentication experiences. Delivered pixel-perfect UI implementations translating complex design requirements into production-ready features while maintaining 99% design fidelity. Built real-time communication features using Socket.io for instant identity verification feedback, enhancing user experience with live status updates and notifications. Collaborated with product and design teams to implement innovative identification workflows improving client conversion rates and user satisfaction.
Senior Frontend Developer at Amygdala LTD
June 1, 2023 - September 3, 2025Architected and developed a real-time identification platform with React.js, Redux, Material UI, and Socket.io delivering secure and responsive user authentication experiences. Delivered pixel-perfect UI implementations translating complex design requirements into production-ready features maintaining 99% design fidelity. Built real-time communication features using Socket.io for instant identity verification feedback enhancing user experience with live status updates and notifications. Collaborated with product and design teams to implement innovative identification workflows improving client conversion rates and user satisfaction.
Lead Frontend Developer at IMYOURDOC
January 31, 2021 - September 3, 2025Diagnosed and resolved critical performance bottlenecks in a React.js-based telemedicine application, improving app stability. Led cross-functional collaboration with backend developers to seamlessly integrate video calling, chat, and patient data features with server-side medical record systems. Optimized real-time communication features ensuring HIPAA-compliant video calls, instant messaging, and file sharing performed reliably under high concurrent user loads.
Senior Frontend Developer at Amygdala B Ltd
January 1, 2021 - June 30, 2023Built a biometric identification product with React.js, Redux, Material UI, and Socket.io to support real-time functionality. Mentored junior developers and improved onboarding processes. Delivered pixel-perfect, innovative features across multiple client products with a strong focus on top-tier user experience.
Lead Frontend Developer at IMYOURDOC
January 1, 2021 - September 3, 2025Diagnosed and resolved critical performance bottlenecks in a React.js-based telemedicine application, improving app stability. Led cross-functional collaboration with backend developers to seamlessly integrate video calling, chat, and patient data features with server-side medical record systems. Optimized real-time communication features ensuring HIPAA-compliant video calls, instant messaging, and file sharing performed reliably under high concurrent user loads.
Lead Frontend Developer at IMYOURDOC
January 1, 2021 - September 3, 2025Diagnosed and resolved critical performance bottlenecks in a React.js-based telemedicine application improving app stability. Led cross-functional collaboration with backend developers to integrate video calling, chat, and patient data features with server-side medical record systems. Optimized real-time communication features ensuring HIPAA-compliant video calls, instant messaging, and reliable file sharing under high concurrent user loads.
Senior Frontend Developer at Amygdala Ltd
January 1, 2021 - June 30, 2023Worked on the development of a cutting-edge identification product utilizing React.js, Redux, Material UI, CSS, and HTML, along with Socket.io for real-time capabilities. Mentored and empowered junior developers, facilitating their growth and streamlining onboarding for new team members. Delivered pixel-perfect designs and innovative features for new client products, ensuring top-tier user experience.
Senior Frontend Developer at Amygdala Ltd
January 1, 2021 - June 1, 2023Developed a cutting-edge identification product using React.js, Redux, Material UI, CSS, and HTML with real-time capabilities via Socket.io. Mentored junior developers facilitating growth and streamlined onboarding. Delivered pixel-perfect designs and innovative features for new client products ensuring top-tier user experience.
Senior Frontend Developer at UNIKRN.COM
March 31, 2020 - September 3, 2025Developed high-stakes betting features for a live iGaming platform using React.js, implementing real-time odds updates, live betting interfaces, and secure payment integrations. Collaborated with cross-functional teams including product managers, designers, and QA engineers to deliver gambling regulation-compliant features within tight release schedules. Architected reusable component library for betting interfaces (odds displays, bet slips, live scoreboards), accelerating feature development and ensuring consistent UX across all gaming verticals.
Senior Frontend Developer at UNIKRN.COM
March 1, 2020 - September 3, 2025Developed high-stakes betting features for a live iGaming platform using React.js, implementing real-time odds updates, live betting interfaces, and secure payment integrations. Collaborated with cross-functional teams including product managers, designers, and QA engineers to deliver gambling regulation-compliant features within tight release schedules. Architected reusable component library for betting interfaces (odds displays, bet slips, live scoreboards), accelerating feature development and ensuring consistent UX across gaming verticals.
Senior Frontend Developer at UNIKRN.COM
March 1, 2020 - September 3, 2025Developed high-stakes betting features for a live iGaming platform using React.js, implementing real-time odds updates, live betting interfaces, and secure payment integrations. Collaborated with cross-functional teams including product managers, designers, and QA engineers to deliver gambling regulation-compliant features within tight release schedules. Architected reusable component library for betting interfaces (odds displays, bet slips, live scoreboards) accelerating feature development and ensuring consistent UX across all gaming verticals.
Senior Frontend Developer (Lead / IMyourDoc) at IMyourDoc
January 1, 2020 - January 1, 2021Diagnosed and resolved critical frontend performance issues in React.js, reducing errors and improving platform stability. Led and mentored frontend developers, and partnered with backend teams to integrate complex server-side logic into the frontend.
Senior Frontend Developer at Lead / ImYourDoc
January 1, 2020 - January 31, 2021Diagnosed and resolved front-end performance issues in React.js, enhancing website stability and significantly reducing errors and crashes. Partnered with back-end developers to seamlessly integrate user-facing elements with robust server-side logic. Mentored, led and onboarded frontend developers, fostering growth and elevating team performance. Led front-end initiatives that significantly reduced error rates and improved UX.
Senior Frontend Developer at Lead / Imyourdoc
January 1, 2020 - January 1, 2021Diagnosed and resolved front-end performance issues in React.js, enhancing website stability and reducing errors and crashes. Partnered with back-end developers for seamless integration of user-facing elements with server-side logic. Mentored and onboarded frontend developers, fostering growth and elevating team performance. Led front-end initiatives that significantly reduced error rates and improved UX.
Senior Frontend Developer at Unikrn.com
February 1, 2019 - March 31, 2020Collaborated with a dynamic team to innovate and implement cutting-edge features for the iGaming betting platform, ensuring top-notch functionality and quality standards. Proactively identified and resolved defects, enhancing user experience and boosting customer satisfaction. Designed and developed reusable React.js components, streamlining future development processes.
Senior Frontend Developer at Unikrn.com
February 1, 2019 - March 1, 2020Collaborated with a dynamic team to innovate and implement cutting-edge features for the iGaming betting platform. Proactively identified and resolved defects to enhance user experience and increase customer satisfaction. Designed and developed reusable React.js components to streamline future development processes.
Senior Frontend Developer at Tronic Innovation GmbH
January 31, 2019 - September 3, 2025Developed and maintained dual-platform applications using React.js for web and React Native for mobile, ensuring code reusability and consistent user experience across iOS, Android, and web platforms. Led cross-functional collaboration with product managers, designers, and QA teams to deliver projects on schedule and within budget constraints, maintaining 98% on-time delivery rate. Architected responsive and dynamic user interfaces optimized for multiple screen sizes and devices, implementing modern design patterns.
Senior Frontend Developer at Tronic Innovation GMBH
January 1, 2019 - September 3, 2025Developed and maintained dual-platform applications using React.js for web and React Native for mobile, ensuring code reusability and consistent user experience across iOS, Android, and web platforms. Led cross-functional collaboration with product managers, designers, and QA teams to deliver projects on schedule and within budget constraints, maintaining 98% on-time delivery rate. Architected responsive and dynamic user interfaces optimized for multiple screen sizes and devices, implementing modern design patterns.
Senior Frontend Developer at Tronic Innovation GmbH
January 1, 2019 - September 3, 2025Developed and maintained dual-platform applications using React.js for web and React Native for mobile ensuring code reusability and consistent user experience across iOS, Android, and web platforms. Led cross-functional collaboration with product managers, designers, and QA teams to deliver projects on schedule and within budget constraints maintaining 98% on-time delivery rate. Architected responsive and dynamic user interfaces optimized for multiple screen sizes and devices implementing modern design patterns.
CEO & Founder at Next Step d.o.o.
June 1, 2018 - PresentFounded and operated a remote development company focused on JavaScript/React frontend solutions for international B2B clients. Managed client relationships, project scoping, and delivery across multiple concurrent engagements.
CEO & Founder at Self-employed
June 1, 2018 - PresentFounded a specialized self-employed development company focusing on JavaScript/React frontend solutions, establishing a sustainable contract/freelance business model with international B2B clients. Developed direct client relationships across healthcare, fintech, and gaming sectors, maintaining 95% client retention through high-quality deliverables and reliable remote collaboration. Established efficient remote work processes for seamless collaboration with international teams, becoming a trusted technical partner for complex frontend development projects.
Founder & CEO at Self-employed (Specialized development company)
June 1, 2018 - PresentFounded a specialized self-employed development company focusing on JavaScript/React frontend solutions, establishing a sustainable contract/freelance business model with international B2B clients. Developed direct client relationships across healthcare, fintech, and gaming sectors, maintaining 95% client retention through high-quality deliverables and reliable remote collaboration. Established efficient remote work processes for seamless collaboration with international teams, becoming a trusted technical partner for complex frontend development projects.
CEO & Founder at Kristijan Bošnjak specialized development company
June 1, 2018 - PresentFounded a specialized self-employed development company focusing on JavaScript/React frontend solutions. Established a sustainable contract/freelance business model with international B2B clients. Developed direct client relationships across healthcare, fintech, and gaming sectors maintaining 95% client retention through high-quality deliverables and reliable remote collaboration. Established efficient remote work processes for seamless collaboration with international teams becoming a trusted technical partner for complex frontend development projects.
CEO & Founder at Next Step d.o.o
June 1, 2018 - November 27, 2024Founded and spearheaded NS, a thriving remote development company specializing in JavaScript/React frontend solutions, designed for self-employment and B2B remote collaboration. Drove B2B growth through innovative frontend solutions and remote collaboration. Achieved high client satisfaction and recurring revenue with a dedicated team. Pioneered self-employment model, ensuring sustainable business success.
CEO & Founder at Next Step d.o.o
June 1, 2018 - June 12, 2024Founded and led a remote development company specializing in JavaScript/React frontend solutions designed for self-employment and B2B remote collaboration. Drove B2B growth, achieved high client satisfaction with a dedicated team, and pioneered a sustainable self-employment model.
Senior Frontend Developer at Tronic Innovation GmbH
March 1, 2018 - January 31, 2019Worked on the development and maintenance of a React and React Native application, enhancing user experience through strategic bug fixes and feature enhancements. Collaborated with cross-functional teams to ensure project objectives were achieved on time and within budget. Designed and maintained dynamic user interfaces and products utilizing React.js, driving innovation and efficiency.
Senior Frontend Developer at Tronic Innovation GmbH
March 1, 2018 - January 1, 2019Developed and maintained React and React Native applications, improving user experience through strategic bug fixes and feature enhancements. Collaborated with cross-functional teams to meet project objectives on time and within budget. Designed and maintained dynamic user interfaces utilizing React.js, driving innovation and efficiency.
Full-stack Developer at IDATA d.o.o.
January 1, 2018 - September 3, 2025Led end-to-end product development for a startup initiative, from initial concept through deployment, including technical architecture planning, comprehensive documentation, and stakeholder presentations. Built scalable web applications using modern full-stack technologies: PHP/Symfony for backend APIs, PostgreSQL for data management, and JavaScript/Backbone.js for interactive frontend experiences.
Full-stack Developer at IDATA d.o.o.
January 1, 2018 - September 3, 2025Led end-to-end product development for a startup initiative from initial concept through deployment, including technical architecture planning, comprehensive documentation, and stakeholder presentations. Built scalable web applications using modern full-stack technologies: PHP/Symfony for backend APIs, PostgreSQL for data management, and JavaScript/Backbone.js for interactive frontend experiences.
Full Stack Developer at IDATA d.o.o.
January 1, 2018 - September 3, 2025Led end-to-end product development for a startup initiative from initial concept through deployment including technical architecture planning, comprehensive documentation, and stakeholder presentations. Built scalable web applications using modern full-stack technologies: PHP/Symfony for backend APIs, PostgreSQL for data management, and JavaScript/Backbone.js for interactive frontend experiences.
Full Stack Developer at Know-How
January 1, 2018 - June 30, 2018Development of a start-up project from scratch, working as a full-stack developer in PHP (Symfony), Backbone.js, JS and Postgres. Assisted in the development and maintenance of front-end web applications, resulting in a positive impact on the company's overall performance. Utilized PHP (Symfony) and PostgreSQL to create scalable solutions. Enhanced front-end applications with Backbone.js and JavaScript.
Full Stack Developer at Know-How
January 1, 2018 - June 1, 2018Developed a startup project from scratch as a full-stack developer using PHP (Symfony), Backbone.js, JavaScript, and Postgres. Assisted in front-end web applications maintenance, enhancing overall company performance. Created scalable solutions and enhanced front-end applications through careful debugging and optimization.
Full Stack Developer at iData
April 1, 2015 - January 31, 2018Spearheaded a startup project, crafting comprehensive documentation and delivering impactful presentations while driving full-cycle development. Engineered robust web applications using cutting-edge technologies: HTML, CSS, PHP, PostgreSQL, JavaScript, Backbone.js, and Symfony. Enhanced user experience by optimizing page elements for lightning-fast loading times and cross-browser compatibility through meticulous debugging. Collaborated effectively with cross-functional teams of developers, designers, and project stakeholders to ensure timely project delivery. Developed scalable back-end components, seamlessly integrating them with dynamic front-end applications to create a cohesive user experience. Upheld the highest quality standards through rigorous code debugging and continuous optimization.
Full Stack Developer at iData
April 1, 2015 - January 1, 2018Led startup project development with thorough documentation and impactful presentations. Engineered robust web applications using HTML, CSS, PHP, PostgreSQL, JavaScript, Backbone.js, and Symfony. Optimized user experience through performance improvements and cross-browser compatibility. Collaborated closely with cross-functional teams to ensure timely delivery and quality.
Education
Master of Information Technology at Polytechnic of Zagreb
January 1, 2016 - December 31, 2016Master of Information Technology at Polytechnic of Zagreb
January 1, 2016 - December 31, 2016Master's Degree, Information Technology at Zagreb University of Applied Sciences
January 1, 2010 - January 1, 2016Gymnasium High School at Gymnasium High School
January 1, 2006 - January 1, 2010Master's Degree at Zagreb University of Applied Sciences
January 1, 2010 - January 1, 2016Master's Degree at Zagreb University of Applied Sciences
January 1, 2010 - January 1, 2016Master of Information Technology at Polytechnic of Zagreb
January 1, 2016 - January 1, 2016Qualifications
Gymnasium High school
January 1, 2006 - January 1, 2010Gymnasium High School
January 1, 2006 - January 1, 2010Industry Experience
Software & Internet, Financial Services, Healthcare, Gaming, Professional Services, Agriculture & Mining
Skills
Experience Level
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Intermediate
Intermediate
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