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Hi, I’m Sebastian, a seasoned full-stack developer with over a decade of experience building scalable web applications using React, Next.js, Node.js, and Kubernetes. I enjoy turning complex requirements into robust, maintainable software and mentoring teams to deliver high-quality results. I thrive in fast-paced environments, focusing on cloud-native architectures, API integrations, and performant frontends. I value collaboration, continuous learning, and measurable improvements in performance, reliability, and user experience.…Hi, I’m Sebastian, a seasoned full-stack developer with over a decade of experience building scalable web applications using React, Next.js, Node.js, and Kubernetes. I enjoy turning complex requirements into robust, maintainable software and mentoring teams to deliver high-quality results. I thrive in fast-paced environments, focusing on cloud-native architectures, API integrations, and performant frontends. I value collaboration, continuous learning, and measurable improvements in performance, reliability, and user experience.

Sebastian Mroz

Front-End Developer, Web Developer, Full Stack Developer, +5

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Hi, I’m Sebastian, a seasoned full-stack developer with over a decade of experience building scalable web applications using React, Next.js, Node.js, and Kubernetes. I enjoy turning complex requirements into robust, maintainable software and mentoring teams to deliver high-quality results. I thrive in fast-paced environments, focusing on cloud-native architectures, API integrations, and performant frontends. I value collaboration, continuous learning, and measurable improvements in performance, reliability, and user experience.…Hi, I’m Sebastian, a seasoned full-stack developer with over a decade of experience building scalable web applications using React, Next.js, Node.js, and Kubernetes. I enjoy turning complex requirements into robust, maintainable software and mentoring teams to deliver high-quality results. I thrive in fast-paced environments, focusing on cloud-native architectures, API integrations, and performant frontends. I value collaboration, continuous learning, and measurable improvements in performance, reliability, and user experience.

Available to hire

Hi, I’m Sebastian, a seasoned full-stack developer with over a decade of experience building scalable web applications using React, Next.js, Node.js, and Kubernetes. I enjoy turning complex requirements into robust, maintainable software and mentoring teams to deliver high-quality results.

I thrive in fast-paced environments, focusing on cloud-native architectures, API integrations, and performant frontends. I value collaboration, continuous learning, and measurable improvements in performance, reliability, and user experience.

Skills

Experience Level

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Intermediate

Intermediate

Intermediate

Intermediate

Intermediate

Language

Polish

Fluent

English

Fluent

Work Experience

Senior Software Engineer at Globant

August 1, 2025 - October 22, 2025

Designed and implemented full-stack web applications using React, Next.js, Node.js, TypeScript, Redux, and Material UI for e-commerce API integrations, delivering scalable solutions across microservices. Led Kubernetes-deployed services and CI/CD pipelines with Docker, Jenkins, and GitHub Actions, increasing deployment efficiency and reliability. Architected RESTful and GraphQL APIs, integrated third-party and internal microservices, enabling real-time data flows across platforms. Collaborated with cross-functional teams, provided technical mentorship, and conducted code reviews to improve quality. Optimized frontend performance with SSR/SSG, achieving faster load times and improved SEO. Built automated test suites with Jest, Cypress, and Playwright, achieving high coverage and reducing production issues. Implemented event-driven communication using Kafka and RabbitMQ to ensure data reliability in high-traffic environments. Implemented AWS-based cloud infrastructure (EC2, S3, RDS, Lamb

Senior Software Engineer at Globant

August 1, 2025 - October 22, 2025

Developed a responsive, single-page health care platform using React, HTML5, CSS3, and Node.js; integrated AI-assisted diagnostics; improved appointment accuracy by 35%. Implemented lead capture workflows connected to Mailchimp and Google Sheets, increasing pre-launch health care service sign-ups. Created dynamic patient dashboards with parallax scrolling (JS/GSAP), enhancing UI responsiveness and engagement.

Senior Software Engineer at Globant

June 1, 2025 - October 2, 2025

Led the development of a responsive, high-traffic digital platform for a global logistics client, using React, Next.js, TailwindCSS, and Material UI. Collaborated with distributed teams via Git, Jira, and Slack. Implemented adaptive design to optimize cross-device performance, boosting customer satisfaction by 18%. Mentored junior developers on React hooks, Redux, and Storybook-driven component architecture. Improved UI rendering performance by integrating Webpack, Babel, and Vite, reducing page load times by 34% and raising Lighthouse scores. Built reusable micro frontends with a microservices-aligned architecture, enabling deployment across applications and reducing release cycles by 25%. Integrated RESTful APIs and GraphQL for real-time data, ensuring reliable contract-based communication with backend services via Swagger and Postman. Established CI/CD pipelines using GitHub Actions and Docker for automated deployments to AWS S3 and CloudFront. Implemented automated testing with Jes

Senior Software Engineer at Globant

June 1, 2025 - October 2, 2025

Led the development of a responsive, high-traffic digital platform for a global logistics client using React, Next.js, TailwindCSS, and Material UI; collaborated with distributed teams via Git, Jira, and Slack; implemented adaptive design to optimize cross-device performance; mentored junior developers in React hooks, state management with Redux, and component-driven architecture using Storybook; improved customer satisfaction scores by 18%, and reduced load times through build optimizations; developed reusable micro frontends for a microservices-aligned architecture and faster release cycles; integrated RESTful APIs and GraphQL for real-time data, and established CI/CD pipelines with GitHub Actions and Docker to AWS S3/CloudFront; maintained AWS cloud services and Cognito authentication.

Senior Software Engineer at Netguru

June 1, 2022 - October 22, 2025

Developed enterprise web apps using React, Next.js, Node.js, TypeScript, Redux, and Angular, integrating multiple REST APIs and improving data retrieval speed by 30%. Worked on microservices architectures with Docker, Kubernetes, and AWS ECS, ensuring scalability and resilience. Implemented SSR and API-driven static generation with Next.js, boosting performance and SEO. Built real-time messaging between microservices and frontend using WebSockets, Kafka, and RabbitMQ. Designed and optimized PostgreSQL and MongoDB databases with Prisma and Mongoose, resulting in faster queries. Authored unit and E2E tests with Jest, Cypress, and Playwright, reducing production incidents. Collaborated with Agile teams; mentored juniors; led API integrations with external services for e-commerce platforms. Enhanced frontend component libraries with Material UI, TailwindCSS, StoryBook for consistency.

Senior Software Engineer at Netguru

June 1, 2022 - October 22, 2025

Built large-scale e-commerce web apps using React, Node.js, HTML5, and CSS3; maintained high uptime. Implemented dynamic product catalogs with real-time updates using MongoDB and Express, improving operational efficiency by 38%. Integrated marketing forms to Mailchimp and Airtable, boosting pre-launch interest by 30%. Created responsive landing pages with React and GSAP animations, increasing engagement by 20%. Optimized frontend and assets for 45% faster page loads and improved SEO; integrated payment gateway/API connections.

Senior Software Engineer at Netguru

June 1, 2022 - October 2, 2025

Developed client-facing web applications with React, Angular, and Vue.js, delivering responsive layouts across desktop and mobile. Built reusable front-end components with TypeScript, Redux, and RxJS to reduce duplication and improve consistency. Integrated REST APIs and GraphQL endpoints, validating workflows with Postman. Introduced advanced Git workflows, improving collaboration and reducing integration conflicts by 40%. Led front-end optimization with Webpack, Babel, and Vite, achieving a 20% reduction in bundle sizes and improved runtime performance. Implemented E2E testing with Cypress and Playwright, lowering post-release defects by 30%. Worked in fully remote agile settings, mentored juniors, and partnered with designers to ensure accessibility and high-quality UI/UX.

Senior Software Engineer at Netguru

June 1, 2022 - October 2, 2025

Developed client-facing web applications with React, Angular, and Vue.js; designed reusable front-end components with TypeScript, Redux, and RxJS; built integration layers consuming REST APIs and GraphQL endpoints with testing via Postman; introduced advanced Git workflows; led front-end optimization with Webpack, Babel, and Vite; implemented E2E testing with Cypress and Playwright; collaborated in fully remote agile settings; mentored junior developers and partnered with designers to deliver accessible, pixel-perfect UI.

Senior Software Engineer at Valtech

February 1, 2018 - October 22, 2025

Assisted in the development of web applications using React, Angular, and Node.js; developed RESTful APIs and database integrations with PostgreSQL and MongoDB; participated in Agile software development cycles, providing code reviews, testing, and collaboration to improve project delivery. Implemented responsive and interactive UI components using Material UI, TailwindCSS, and CSS3, enhancing user experience across platforms. Supported CI/CD pipelines and cloud deployments on AWS and Docker, contributing to faster and more reliable application releases.

Senior Software Engineer at Valtech

February 1, 2018 - October 22, 2025

Contributed to high-performance advertising infrastructure handling billions of requests daily using Node.js, React, and MongoDB, achieving sub-second response times across campaigns. Built real-time analytics dashboards with D3.js and React, cutting manual reporting by 60%. Optimized backend services and queries for ad serving with PostgreSQL, increasing throughput by 35% under heavy load. Implemented lead generation/tracking forms via Google Sheets and Mailchimp, boosting lead capture by 22%. Built responsive front-end components with HTML5, CSS3, and JS, enhancing user experience and accessibility for diverse client platforms.

Software Engineer at Valtech

February 1, 2018 - October 2, 2025

Supported development of web applications using JavaScript, jQuery, and AngularJS, delivering responsive layouts and cross-browser compatibility. Contributed to adaptive HTML5 and CSS3 designs, learning UI/UX best practices. Participated in integration testing with Mocha and Jest, reducing defects pre-release and supporting faster iterations. Collaborated with backend teams to consume RESTful APIs and implement basic data binding with AngularJS, reinforcing frontend-backend collaboration. Participated in agile ceremonies and contributed to iterative software delivery.

Software Engineer at Valtech

February 1, 2018 - October 2, 2025

Supported web app development using JavaScript, jQuery, and AngularJS; assisted in implementing adaptive HTML5/CSS3 designs and UI/UX best practices; contributed to integration testing with Mocha and Jest; consumed RESTful APIs and performed basic data binding; participated in agile ceremonies and frontend-backend collaboration.