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I am a Senior Software Engineer specializing in Golang backend development and modern frontends with React and Angular. I have a proven record delivering cloud-native, enterprise solutions across Healthcare, Finance, and IT Consulting sectors, with expertise in microservices, gRPC/REST APIs, and event-driven architectures. I am skilled in Azure, AWS, and DevOps automation, and passionate about clean code, team leadership, and continuous learning across Golang, Python, and C#. Throughout my career, I've successfully migrated legacy systems to scalable microservices, optimized performance-critical backend services, and built event-driven pipelines that handle high-throughput data. I am committed to improving developer workflows and automating infrastructure provisioning, with a strong focus on observability and reliability. I enjoy mentoring teams and contributing to knowledge sharing to promote engineering best practices.…I am a Senior Software Engineer specializing in Golang backend development and modern frontends with React and Angular. I have a proven record delivering cloud-native, enterprise solutions across Healthcare, Finance, and IT Consulting sectors, with expertise in microservices, gRPC/REST APIs, and event-driven architectures. I am skilled in Azure, AWS, and DevOps automation, and passionate about clean code, team leadership, and continuous learning across Golang, Python, and C#. Throughout my career, I've successfully migrated legacy systems to scalable microservices, optimized performance-critical backend services, and built event-driven pipelines that handle high-throughput data. I am committed to improving developer workflows and automating infrastructure provisioning, with a strong focus on observability and reliability. I enjoy mentoring teams and contributing to knowledge sharing to promote engineering best practices.

Nikola Kartelo

Developer, Programmer, Back-End Developer, +2

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I am a Senior Software Engineer specializing in Golang backend development and modern frontends with React and Angular. I have a proven record delivering cloud-native, enterprise solutions across Healthcare, Finance, and IT Consulting sectors, with expertise in microservices, gRPC/REST APIs, and event-driven architectures. I am skilled in Azure, AWS, and DevOps automation, and passionate about clean code, team leadership, and continuous learning across Golang, Python, and C#. Throughout my career, I've successfully migrated legacy systems to scalable microservices, optimized performance-critical backend services, and built event-driven pipelines that handle high-throughput data. I am committed to improving developer workflows and automating infrastructure provisioning, with a strong focus on observability and reliability. I enjoy mentoring teams and contributing to knowledge sharing to promote engineering best practices.…I am a Senior Software Engineer specializing in Golang backend development and modern frontends with React and Angular. I have a proven record delivering cloud-native, enterprise solutions across Healthcare, Finance, and IT Consulting sectors, with expertise in microservices, gRPC/REST APIs, and event-driven architectures. I am skilled in Azure, AWS, and DevOps automation, and passionate about clean code, team leadership, and continuous learning across Golang, Python, and C#. Throughout my career, I've successfully migrated legacy systems to scalable microservices, optimized performance-critical backend services, and built event-driven pipelines that handle high-throughput data. I am committed to improving developer workflows and automating infrastructure provisioning, with a strong focus on observability and reliability. I enjoy mentoring teams and contributing to knowledge sharing to promote engineering best practices.

Available to hire

I am a Senior Software Engineer specializing in Golang backend development and modern frontends with React and Angular. I have a proven record delivering cloud-native, enterprise solutions across Healthcare, Finance, and IT Consulting sectors, with expertise in microservices, gRPC/REST APIs, and event-driven architectures. I am skilled in Azure, AWS, and DevOps automation, and passionate about clean code, team leadership, and continuous learning across Golang, Python, and C#.

Throughout my career, I’ve successfully migrated legacy systems to scalable microservices, optimized performance-critical backend services, and built event-driven pipelines that handle high-throughput data. I am committed to improving developer workflows and automating infrastructure provisioning, with a strong focus on observability and reliability. I enjoy mentoring teams and contributing to knowledge sharing to promote engineering best practices.

Skills

.NET

Python

Azure

Experience Level

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Intermediate

Language

Croatian

Fluent

English

Fluent

Work Experience

Software Engineer at Four of them, LLC

July 1, 2025 - August 15, 2025

Led the migration of performance-critical services from legacy monoliths to Golang microservices utilizing gRPC and REST, improving response times by 40% and eliminating technical debt. Refactored monolithic commerce APIs into Golang microservices deployed on Docker and Kubernetes (AKS), reducing deployment time by 70%. Developed event-driven data synchronization pipelines using Go and Kafka, boosting throughput by 80%. Rebuilt legacy .NET/WCF APIs as Go services, halving inter-service latency. Implemented asynchronous task management with RabbitMQ and Azure Service Bus, increasing message success rates by 40%. Designed ETL workflows in Python with Airflow, cutting nightly data sync from 3 hours to 20 minutes. Automated infrastructure provisioning using Terraform and Go CDK, reducing environment setup times by 85%. Built containerized integration test suites and implemented JWT-based SSO integration with Azure AD. Engineered a distributed search engine with Go and Elasticsearch, delive

Software Engineer at Three of them, LLC

October 1, 2022 - August 15, 2025

Developed enterprise-grade web applications using Golang (Gin) and ASP.NET MVC with SQL Server to replace outdated business tools, increasing efficiency by 45%. Built responsive user interfaces with jQuery and Bootstrap and integrated them with Golang backend APIs, enhancing user engagement by 30%. Automated backend operations using Go microservices and Windows Services, reducing operational errors by 60%. Designed real-time dashboards with SSRS, Power BI, and Go REST APIs, improving business visibility. Established CI/CD pipelines with TeamCity, Octopus Deploy, and GoReleaser, cutting deployment cycles in half. Refactored monolithic codebases using design patterns, migrating modules to Golang for better testability and faster bug resolution. Integrated third-party REST and SOAP APIs to unify fragmented workflows. Prototyped cross-platform mobile apps with Flutter and Firebase backed by Go services. Optimized SQL Server performance with indexing, query tuning, and asynchronous processi

Software Developer at Spring thesign, LLC

December 1, 2020 - August 15, 2025

Engineered custom WordPress and WooCommerce platforms using PHP, JavaScript, and SCSS, optimizing time-to-first-byte and mobile responsiveness. Developed high-performance geospatial data services with .NET Core and Trimble MAP SDKs, reducing map rendering latency by 50%. Refactored GIS web portals with Angular achieving WCAG 2.1 AA compliance, enhancing user experience and accessibility for government clients. Automated spatial ETL pipelines using Python (GDAL, ArcPy) and PostgreSQL/PostGIS, improving accuracy and reducing manual tasks by over 40%. Designed and deployed RESTful APIs with ASP.NET Core and Entity Framework Core, retiring legacy SOAP services to enable seamless system interoperability. Containerized GIS modules with Docker and OpenShift, cutting environment setup times by 70%. Implemented secure authentication using OAuth2 and SAML for mapping tools compliant with enterprise security standards. Created brand identity and responsive UI designs using Figma and Adobe tools.