Dejan Hergelic — Senior Full Stack Software Engineer

Expertise in Full Stack Web, Back-End Web.

Last verified on September, 2026

Core Skills

Bio Summary

Senior Full Stack Engineer with 10+ years of experience building scalable SaaS and eCommerce platforms. Strong in TypeScript, Python, C#/.NET, Java, React, cloud-native microservices, AWS/GCP, Docker, and Kubernetes. Experienced in production AI systems using LLMs, RAG, and semantic search.

Technical Skills

Programming Languages	Java, PHP, Python, TypeScript
JavaScript Frameworks	Angular, Express, NestJS, Next.js, Node.js, Nuxt, React, Vue.js
Python Frameworks	Django, FastAPI
AI & Machine Learning	Hugging Face, LangChain, OpenAI
PHP Frameworks	Laravel, Symfony
.NET Platform	.NET
PHP Libraries and Tools	PHPUnit
Python Libraries and Tools	pytest
Java Frameworks	Spring Boot
JavaScript Libraries and Tools	Vite, Webpack
Databases & Management Systems / ORM	Clickhouse, Elasticsearch, Firebase, MongoDB, MySQL, PostgreSQL, Redis
UI Frameworks, Libraries, and Browsers	Tailwind CSS
Cloud Platforms, Services & Computing	AWS, Firebase, GCP
Amazon Web Services	AWS Kinesis
Google Cloud Platform	Google Cloud Pub/Sub
QA, Test Automation, Security	Cypress, Jest, PHPUnit, Playwright, pytest
Virtualization, Containers and Orchestration	Docker, Kubernetes
SDK / API and Integrations	FastAPI, GraphQL
Version Control	Github Actions
Deployment, CI/CD & Administration	GitLab CI
Message/Queue/Task Brokers	Kafka, RabbitMQ
Web/App Servers, Middleware	Nginx
Methodologies, Paradigms and Patterns	Scrum
Other Technical Skills	Jetstream, Pest

Work Experience

Senior Software Engineer (AI Insurance)

Duration: Dec '25 - May '26

Built full-stack features for an AI-powered insurance platform using TypeScript (Node.js, React/Next.js) and Python
Developed and maintained REST APIs for policy, claims, and risk-related services
Deployed microservices on GCP using Docker for scalable, reliable processing
Designed data models in PostgreSQL and MongoDB for insurance and transaction data
Integrated AI/LLM features for risk analysis, claims automation, and internal workflows

Technologies: TypeScript (Node.js, React/Next.js), Python, PostgreSQL, MongoDB, Docker, GCP, AI/LLM integrations

Senior Full Stack - AI Engineer - Altoros (AI-driven web applications)

Duration: Jan '21 - Sep '25

Built and shipped AI-driven web applications using TypeScript and Python, owning features from backend to production.
Developed frontend interfaces with Next.js, delivering fast, maintainable web apps aligned with backend APIs.
Designed event-driven systems with Kafka, RabbitMQ, Redis Streams, AWS Kinesis, Google Pub/Sub, and NATS JetStream for real-time and async processing.
Integrated LLM-based features using OpenAI, LangChain, and Hugging Face for automation and intelligent workflows.
Designed and optimized REST and GraphQL APIs, improving performance and reliability.
Improved PostgreSQL/MySQL performance and caching using Redis.
Strengthened CI/CD and DevOps using Docker and GitLab, deploying services on AWS and GCP.
Worked in a Scrum team, collaborating through GitHub PRs and code reviews

Technologies: TypeScript, Python, Next.js, Kafka, RabbitMQ, Redis Streams, AWS Kinesis, Google Pub/Sub, NATS JetStream, OpenAI, LangChain, Hugging Face, REST, GraphQL, PostgreSQL, MySQL, Redis, Docker, GitLab, AWS, GCP

Senior Web Engineer - Ciklum (Scalable backend systems and customer-facing web platforms)

Duration: Jan '18 - Apr '21

Built scalable backend systems using Java (Spring Boot) and C#/.NET, delivering reliable APIs and distributed services for production applications.
Developed customer-facing features with React and Next.js, improving performance and usability across web platforms.
Designed REST APIs and async workflows supporting event-driven and cloud-native architectures.
Worked with PostgreSQL, MongoDB, and Redis, improving data performance and scalability.
Deployed and maintained services on AWS using Docker and CI/CD pipelines for reliable delivery.
Collaborated closely with product and engineering teams to ship clean, maintainable features quickly.

Technologies: Java (Spring Boot), C#/.NET, React, Next.js, PostgreSQL, MongoDB, Redis, AWS, Docker, CI/CD

Senior Software Engineer - SoftTeco (Backend services and APIs development)

Duration: Feb '17 - Feb '18

Built backend services and APIs using TypeScript and Node.js, delivering scalable functionality for client web products.
Developed and maintained backend components in PHP, supporting existing systems and integrations.
Designed and implemented REST APIs, focusing on clean contracts and long-term maintainability.
Improved performance and reliability across services through refactoring and optimization.
Supported deployment and CI/CD workflows, ensuring stable releases.
Collaborated closely with designers and engineers to deliver features on schedule.

Technologies: TypeScript, Node.js, PHP, REST APIs, CI/CD

Senior Full Stack Developer - iVisa.com (Core travel-document platform)

Duration: May '14 - Jan '17

Developed the core travel-document platform enabling travelers to apply, pay and receive visas online, using Laravel for backend services and VueJS for the front-end SPA.
Built intuitive application flows, payment interfaces and document-upload modules which significantly reduced drop-off and improved conversion.
Designed and implemented REST APIs, data validation, user-session logic and secure data storage on MySQL with Redis caching.
Added real-time status updates and notification features for applicants (e.g., "Application received", "Visa approved"), improving UX and customer trust.
Automated workflow pipelines: document ingestion, review queue and approval system using Laravel queue workers and Redis.
Deployed and maintained Docker-based CI/CD pipelines ensuring regular releases with minimal downtime and high reli

Technologies: Laravel, VueJS, MySQL, Redis, REST APIs, Docker, CI/CD

Education

Bachelor of Computer Science & Engineering
University of Novi Sad, Novi Sad, Serbia

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