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"Need an engineer who can turn an idea into a polished mobile and web product without costly rewrites? I'm Yevhen, a Mobile App Developer & Frontend Developer with 6+ years of experience in React Native and 15+ production-ready digital projects. I build mobile apps, web frontends, and cross-platform products from idea to launch. My focus is faster delivery, pixel-perfect UI, and scalability. 💻 What I build as a Mobile App Developer | Frontend Developer 15+ mobile apps, MVPs, dashboards and frontend solutions. 6+ years designing scalable mobile and web interfaces. 30-60% less manual work through reusable component systems and automation. 2 platforms covered with React Native and Expo: iOS and Android. 3 product layers managed: mobile, frontend, architecture. 4 stages covered: planning, development, launch, scaling. I work as a mobile app developer with React Native, Expo, TypeScript, React, Next.js, Redux, Tailwind CSS and Styled Components. For Expo product, I provide mobile app developer expertise with OTA updates and EAS build. For React systems, I work as a frontend developer using component architecture and state management. I can also join as a web developer, mobile developer, frontend developer, or React Native engineer. 📱 Mobile app development I create React Native applications for iOS and Android from a single codebase. Each mobile app can include navigation, offline support, push notifications, and API integration. ✔️ 15+ apps shipped - React Native and Expo for iOS and Android ✔️ 2 platforms from 1 codebase - Cross-platform mobile development ✔️ 100% pixel-perfect UI - Figma to React Native component translation ✔️ OTA updates - Expo Application Services for instant deployments ✔️ Offline-first architecture - Local storage and sync strategies ✔️ Push notifications - Firebase Cloud Messaging and APNs ✔️ Native module integration - Camera, geolocation, biometrics, BLE ✔️ Deep linking & navigation - React Navigation and URL-based routing ✔️ App Store & Google Play - Full release and review process ✔️ 60+ FPS animations - Reanimated and gesture-based interactions ✔️ Accessibility - Screen reader support and WCAG-compliant components As a mobile app developer, I build workflows that connect APIs, handle authentication, and deliver smooth user experiences across devices. A second mobile layer can integrate native features when required. My React Native pipelines adapt when platform updates change. 🎨 Frontend, UI/UX. Web development As a Frontend Developer, I build responsive web applications, dashboards, and design systems. I can work as a Frontend Developer specialist, connecting interfaces, state management, API layers, and component libraries through React and Next.js. For data-heavy systems, I apply performance optimization methods and coordinate with a designer when needed. I assess whether TypeScript techniques are justified or simpler logic is safer. I also support mobile-first responsive workflows involving layouts, animations, and accessibility. ⚙️ Core stack and approach ✔️React Native, Expo, TypeScript, JavaScript, React, Next.js, Redux Toolkit ✔️REST API, GraphQL, Firebase, AsyncStorage, SQLite, and EAS deployment ✔️Payment gateway integration, authentication, third-party APIs and mobile automation ✔️Architecture, coding, testing, documentation and production support I can begin as an it consultant, clarify the scope, then continue as the Mobile App Developer responsible for implementation. Depending on the system, I may work as a mobile app developer, provide frontend developer delivery, or take ownership as a Frontend Developer during restructuring and scaling. For legacy environments involving older React codebaKeywords: Full-stack developer, Web development, Mobile app development, API development, Backend development, Frontend development, SaaS development, Startup development, MVP development, Product development, System architecture, Platform development, Next.js developer, React developer, JavaScript, TypeScript, HTML5, CSS3, Responsive design, React Native developer, Expo, Cross-platform apps, iOS development, Android development, Python developer, FastAPI, Django, Flask, REST APIs, Automation engineer, Process automation, Business automation, Workflow automation, ETL pipelines, Data processing, Web scraping, Scrapy, Selenium, Playwright, AI integration, ChatGPT integration, Analytics dashboards, Admin dashboards, Internal tools, CRM systems, Performance optimization, Scalability, Cloud-ready systems, CI/CD, Digital platforms, AI-powered applications, Responsive web design, Web app development, Landing page development, Python automation, Data scraping, Cross-platform mobile apps, Mobile UI development, Python Backend Developer, RestAPI, Rest API, Fast API, PostgreSQL, SQL, Postgres, Scrapping, Data Extraction, Bots, Scripts, React.js, ReactJS, React Js, NextJS, Next Js, Full Stack, FullStack, ReactNative, Mobile App, LLM, RAG, AI Agent, LangChain, Data Pipeline, bot.

Over the last 15 years, I have developed a wide range of applications using Java technologies. Spring / Spring Boot, Hibernate JSP, JSF, Apache Wicket, Apache Struts HTML.CSS, JavaScript, jquery, mySql, postgreSQL, Oracle. My skills are confirmed by certifications: VMWare Spring Certified Profesional OCP (Oracle Certified Professional Java SE 17) SCJP (Sun Certified Java Programmer) SCWCD (Sun Certified Web Component Developer).

Hey👋 == 𝟮𝟮 𝘆𝗲𝗮𝗿𝘀 𝗼𝗳 𝗫𝗣. 𝟭𝟕𝟬 𝗽𝗿𝗼𝗷𝗲𝗰𝘁𝘀. 𝟭𝟬𝟬% 𝘀𝘂𝗰𝗰𝘀𝗲𝘀 𝗿𝗮𝘁𝗲. == ✔𝐅𝐫𝐞𝐞 𝟐𝟎 𝐡𝐨𝐮𝐫𝐬 𝐨𝐟 𝐩𝐥𝐚𝐧𝐧𝐢𝐧𝐠 𝐟𝐨𝐫 𝐲𝐨𝐮𝐫 𝐧𝐞𝐰 𝐩𝐫𝐨𝐣𝐞𝐜𝐭 (DM "Free") ✔𝐅𝐫𝐞𝐞 𝐜𝐨𝐝𝐞 𝐫𝐞𝐯𝐢𝐞𝐰 𝐟𝐨𝐫 𝐲𝐨𝐮𝐫 𝐞𝐱𝐢𝐬𝐭𝐢𝐧𝐠 𝐩𝐫𝐨𝐣𝐞𝐜𝐭 (DM "Free") Main focus: ✅𝐑𝐞𝐥𝐢𝐚𝐛𝐢𝐥𝐢𝐭𝐲 𝐞𝐧𝐠𝐢𝐧𝐞𝐞𝐫𝐢𝐧𝐠: structured review of your application, architecture, AWS infrastructure, deployment process, monitoring, and operational dependencies, followed by a prioritized remediation roadmap. ✅𝐏𝐎𝐒 𝐚𝐧𝐝 𝐌𝐮𝐥𝐭𝐢-𝐒𝐭𝐨𝐫𝐞 𝐂𝐨𝐦𝐦𝐞𝐫𝐜𝐞: POS, KDS, checkout, payment, catalog, ordering, inventory, loyalty, reporting, and multi-store commerce software for businesses operating across physical locations and online storefronts. ✅𝐈𝐨𝐓 𝐅𝐥𝐞𝐞𝐭 𝐌𝐚𝐧𝐚𝐠𝐞𝐦𝐞𝐧𝐭: build secure IoT, telemetry, remote diagnostics, and predictive maintenance platforms for manufacturers, service teams, and operators managing connected devices at scale. ✅𝐉𝐚𝐯𝐚 𝐄𝐜𝐨𝐬𝐲𝐬𝐭𝐞𝐦 𝐌𝐨𝐝𝐞𝐫𝐧𝐢𝐳𝐚𝐭𝐢𝐨𝐧: modernizes Java-based enterprise systems in controlled stages, including EJB applications, Oracle products, application servers, while preserving critical business functionality. ✅𝐄𝐧𝐭𝐞𝐫𝐩𝐫𝐢𝐬𝐞 𝐒𝐨𝐟𝐭𝐰𝐚𝐫𝐞 𝐑𝐞𝐬𝐜𝐮𝐞: help companies take over, understand, stabilize, and safely continue development of complex Java, Spring, and AWS systems when the existing team, architecture, or delivery process is no longer reliable. ================================================ WE EARN/SAVE MONEY💰 FOR OUR CUSTOMERS by: • allowing their business to expand (or start sometimes:) • automating processes and reducing operational cost • using newer and more efficient technology • long-run cost reduction because of high-quality software. ================= Some tech below =============== ✔ Cloud applications Cloud, serverless, scalable applications, architecture and development for Amazon Web Services (AWS) and Google Cloud Platform (GCP). ✔ AI development and integration Embed AI-powered tools to your business and software: AI analytics, predictive maintenance, LLM, chatbots, ChatGPT integration, AI over your data helping your clients. ✔ Complex system development, API integration and development Develop custom software from A to Z, build sophisticated APIs, integrate third-party APIs, data hubs and gateways. ✔ Big data volumes processing, storage, and analytics Receive, process, store and analyze and send huge volumes of data. Cost-efficient data-focused systems on the cloud. ✔ Internet of things (IoT) Connect and manage thousands of simple and complex devices on the cloud, custom automation, reports and analytics. ✔ Other Workflow automation, Performance optimization, QA automation. Some tech details: ✓ Java/Spring: SpringBoot/Spring Cloud/Spring Web/Spring AI/Spring Security/Spring Data etc. ✓ Java/JavaEE: EJB, JSP/JSF/RichFaces/Oracle ADF, JavaFX ✓ Spring: SpringBoot, Spring MVC, Web, Security, Data, AI ... ✓ Cloud: AWS, Google Cloud, Docker, Kubernetes, ECS, EKS, Cloud-native apps, scalable clusters, zero-downtime deployment. ✓ AI: Codex, Claude, MCP, RAG, Vertex AI. ✓ Databases: Oracle/PostgreSQL/MySQL, PL/SQL, AWS RDS, big volume storage (AWS Redshift, AWS Athena/S3, Aurora, Cassandra, HDFS), Redis, MongoDB, Neo4j, S3/Parquet, JPA, custom ORMs. ✓ Web: Bootstrap, Angular, React, JavaScript, OAuth. ✓ Servers: Tomcat, Weblogic, JBoss/Wildfly, Websphere. ✓ APIs: REST, SOAP, XML-RPC, WebServices, WebSockets, Swagger/OpenAPI. ✓ AWS: Clusters, AWS EC2, AWS Kinesis, AWS Athena, AWS Redshift, AWS DynamoDB, AWS Lambda, AWS IoT, AWS SQS/SNS, AWS CloudFront/Route53/ApiGateway, vast AWS API usage, and automation. ✓ Data streaming: AWS Kinesis, Firehose, SQS/SNS, Kafka, Camel, RabbitMQ. ✓ Performance optimization: JMeter, JProfiler, AWS X-Ray, GTMetrix, Gatling. ✓ Version control: Git, Github, Bitbucket, GitLab, SVN. ✓ CI/CD: Bamboo, Jenkins, Circle CI, Sonar, Bitbucket pipelines, GitHub Actions, AWS CodeBuild/CodeDeploy. ✓ Other: Maven, Nexus, Gradle, Ant. We get things done.

Experienced backend Java developer with over a decade of expertise in developing and maintaining high-quality software solutions. My career includes roles at Accenture, Credit Suisse and GFT Group. Based in Poland, I have also worked in London with Luxoft and Unibet, a leading company in the gambling industry. Top-rated Upwork freelancer, ranked in the top 5% of performers with a 100% Job Success Score. Proficient in Java, Spring Boot, REST APIs, and cloud technologies (AWS). Adept at working with distributed international teams, emphasizing clean code practices and delivering challenging projects. Programming Languages: Java, JavaScript, Scala APIs & Integrations: RESTful APIs, GraphQL, WebSocket, RabbitMQ, JMS, Kafka Cloud & DevOps: AWS (Cloudformation), Docker, CI/CD (Jenkins, GitHub Actions) Frameworks & Tools: Spring Framework, Spring Boot, Hibernate, JPA Version Control: Git, GitLab, Bitbucket Databases: MySQL, PostgreSQL, MongoDB, Redis Testing: JUnit, Mockito, Cucumber, TDD Others: Observability, Keycloak, Angular, Maven, Bash