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I am a seasoned Full Stack Engineer with expertise in C#/.NET and modern web technologies, delivering robust financial and e-commerce applications with a focus on performance, security, and user experience. I am passionate about applying best practices in software architecture, testing, and DevOps to build scalable and maintainable systems. Throughout my career, I have collaborated with cross-functional teams in Agile environments, contributing to complex projects involving backend services, frontend interfaces, test automation, and cloud integration. I continuously seek to expand my skill set across programming languages, frameworks, and cutting-edge AI technologies to drive innovation and efficiency in software development.…I am a seasoned Full Stack Engineer with expertise in C#/.NET and modern web technologies, delivering robust financial and e-commerce applications with a focus on performance, security, and user experience. I am passionate about applying best practices in software architecture, testing, and DevOps to build scalable and maintainable systems. Throughout my career, I have collaborated with cross-functional teams in Agile environments, contributing to complex projects involving backend services, frontend interfaces, test automation, and cloud integration. I continuously seek to expand my skill set across programming languages, frameworks, and cutting-edge AI technologies to drive innovation and efficiency in software development.

Krystian Dajka

Full Stack Developer, Programmer, Developer, +4

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I am a seasoned Full Stack Engineer with expertise in C#/.NET and modern web technologies, delivering robust financial and e-commerce applications with a focus on performance, security, and user experience. I am passionate about applying best practices in software architecture, testing, and DevOps to build scalable and maintainable systems. Throughout my career, I have collaborated with cross-functional teams in Agile environments, contributing to complex projects involving backend services, frontend interfaces, test automation, and cloud integration. I continuously seek to expand my skill set across programming languages, frameworks, and cutting-edge AI technologies to drive innovation and efficiency in software development.…I am a seasoned Full Stack Engineer with expertise in C#/.NET and modern web technologies, delivering robust financial and e-commerce applications with a focus on performance, security, and user experience. I am passionate about applying best practices in software architecture, testing, and DevOps to build scalable and maintainable systems. Throughout my career, I have collaborated with cross-functional teams in Agile environments, contributing to complex projects involving backend services, frontend interfaces, test automation, and cloud integration. I continuously seek to expand my skill set across programming languages, frameworks, and cutting-edge AI technologies to drive innovation and efficiency in software development.

Available to hire

I am a seasoned Full Stack Engineer with expertise in C#/.NET and modern web technologies, delivering robust financial and e-commerce applications with a focus on performance, security, and user experience. I am passionate about applying best practices in software architecture, testing, and DevOps to build scalable and maintainable systems.

Throughout my career, I have collaborated with cross-functional teams in Agile environments, contributing to complex projects involving backend services, frontend interfaces, test automation, and cloud integration. I continuously seek to expand my skill set across programming languages, frameworks, and cutting-edge AI technologies to drive innovation and efficiency in software development.

Skills

Experience Level

Expert

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Intermediate

Work Experience

Senior Full Stack Engineer & Test Engineer at Visa

April 1, 2025 - August 25, 2025

Developed financial web application backend services and secure REST APIs using C#/.NET Framework and ASP.NET MVC. Built frontend dispute management system with React.js including dashboards and data visualizations. Designed and implemented automated testing frameworks with Playwright, Selenium WebDriver, Jasmine, and NUnit. Integrated test pipelines with Azure DevOps for continuous testing. Conducted API, performance, and load testing using Postman and JMeter, integrated with Jenkins pipelines. Optimized SQL Server queries for backend validation. Collaborated within Agile/Scrum teams and documented strategies for knowledge sharing.

Senior Full Stack Engineer at Kforce

July 1, 2024 - August 25, 2025

Implemented e-commerce app using C#, ASP.NET Core, and Angular 16, creating RESTful APIs that improved efficiency by 25%. Engineered PostgreSQL relational database with optimized queries for improved data access speed by 30%. Enhanced UI with React and Bootstrap improving engagement and reducing cart abandonment by 20%. Integrated multiple payment gateways ensuring PCI DSS compliance. Developed invoicing system that boosted conversion rates by 15%.

Senior Software Engineer at Citi

April 1, 2020 - August 25, 2025

Designed and enhanced financial close automation modules with C# .NET for reconciliation and transaction matching. Developed desktop utilities and middleware to integrate ERP systems like SAP and Oracle with Citi's accounting platform. Automated journal entry processes ensuring SOX and GAAP compliance. Created background jobs and Windows services reducing manual reconciliation efforts by 30%. Optimized SQL Server integration for real-time financial reporting and collaborated with QA and finance teams to resolve production issues.

Senior Full Stack Engineer & Test Engineer at Visa

April 1, 2025 - August 25, 2025

Contributed to the development of a C#/.NET Framework and ASP.NET MVC financial web application, building backend services, secure REST API integrations, and transaction validation modules. Designed and built the frontend Dispute Management System using React.js with interactive dashboards and data visualization. Implemented test automation frameworks using Playwright, Selenium WebDriver, Jasmine, and NUnit for functional and integration testing and integrated automated test pipelines with Azure DevOps for continuous testing in CI/CD workflows. Conducted API testing with Postman and performance testing with JMeter, optimized SQL Server queries for backend data validation, and documented testing strategies. Worked in an Agile/Scrum environment collaborating with QA, DevOps, and product teams.

Senior Full Stack Engineer at Kforce

July 1, 2024 - August 25, 2025

Implemented an e-commerce application using C#, ASP.NET Core, and Angular 16, creating RESTful APIs for product listings, user authentication, and order processing increasing system efficiency by 25%. Engineered a relational database with PostgreSQL, optimizing data retrieval which improved speed by 30%. Enhanced UI using React and Bootstrap for responsive design and employed Google Optimize for A/B testing, reducing cart abandonment by 20%. Integrated payment gateways ensuring PCI DSS compliance and developed a subscription invoicing system increasing conversion by 15%.

Senior Software Engineer at Citi

April 1, 2020 - August 25, 2025

Designed and enhanced financial close automation modules in C# .NET supporting reconciliation, account certification, and transaction matching workflows. Developed desktop utilities and middleware services to integrate ERP systems like SAP and Oracle with accounting automation. Implemented journal entry automation ensuring compliance with SOX and GAAP standards. Built Windows services for data imports/exports, reducing manual reconciliation effort by 30%. Optimized SQL Server integration for real-time financial reporting and collaborated closely with QA and finance to resolve critical production issues ensuring data accuracy.