Darko Zivkovic - Technical Lead

Q: Where is Darko based?

Darko is based in Barič, Serbia .

Q: What languages does Darko speak?

Darko speaks the following languages: English (Advanced), Serbian (Intermediate) .

Q: How many years of experience does Darko have?

Darko has at least 10 years of experience. During this time, Darko has worked in at least 3 different roles and for 3 different companies . The average length of individual experience is 3 years and 5 months . Note that Darko may not have shared all experience and actually has more experience.

Q: What is Darko's latest experience?

Darko's most recent position is Technical Lead at Sipod .

Q: What companies has Darko worked for in recent years?

In recent years, Darko has worked for Sipod and Axians Serbia .

Q: Which industries is Darko most experienced in?

Darko is most experienced in industries like Information Technology .

Q: Which business areas is Darko most experienced in?

Darko is most experienced in business areas like Information Technology , Quality Assurance , and Product Development .

Q: Which industries has Darko worked in recently?

Darko has recently worked in industries like Information Technology .

Q: Which business areas has Darko worked in recently?

Darko has recently worked in business areas like Information Technology , Product Development , and Quality Assurance .

Recommended expert

Barič, Serbia

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Experience

Dec 2022 - Present

3 years 7 months

Technical Lead

Sipod

Designed and led the architectural modernization of a mission-critical enterprise application suite, migrating 1M+ lines of legacy code into a modular, service-oriented JavaScript and Node.js architecture with clean API and UI boundaries.
Built high-throughput Node.js and TypeScript API middleware handling async data synchronization between web clients and cloud-hosted SQL repositories, applying REST design principles and efficient JSON payload serialization.
Developed an async data processing engine using Node.js worker threads, queues, and non-blocking I/O, achieving consistent low-latency performance under heavy load.
Architected enterprise web management portals in React and Next.js with Node.js service APIs, TypeORM persistence logic, multi-tenant data access patterns, and automated report generation.
Designed AI-assisted development workflows using Cursor, Claude Code, GitHub Copilot, RAG, MCP server patterns, Agent Skills, and structured prompts to generate tests, refactor code, and validate charting logic.
Reduced SQL Server data retrieval times by 55% through advanced indexing strategies, query refactoring, and schema redesign targeting large-scale analytical workloads consumed by Node.js APIs.
Led a 5-developer team, enforcing code quality standards, Jest testing protocols, AI verification, evaluation, output confirmation, and consistent API design across backend services and React application layers.

Mar 2021 - Nov 2022

1 year 9 months

Senior Software Engineer

Axians Serbia

Built a real-time notification engine using WebSockets, Socket.IO, and event-driven Node.js services to push live updates to connected clients with reliable, low-latency delivery.
Designed responsive React UI components for real-time visualization of high-frequency data streams, applying component-based architecture, memoization, and reactive rendering patterns for smooth user interaction.
Engineered Node.js and Python diagnostic tooling for automated performance profiling, memory monitoring, and production health checks, reducing application resource consumption by 30%.
Refactored legacy service controllers into TypeScript-based Node.js modules using Dependency Injection and Repository pattern, decoupling business logic from data access and improving unit testability.
Containerized distributed Node.js application modules with Docker and integrated them into Jenkins CI/CD pipelines, cutting deployment time from hours to minutes and ensuring environment consistency across stages.
Optimized SQL Server storage through table partitioning and data compression, improving throughput and query performance across multi-terabyte time-series datasets served through backend APIs.
Applied spec-driven AI development with OpenAI API, MCP servers, tool calling, embeddings, vector search, structured prompts, evaluation, and output confirmation to accelerate refactoring, test generation, and release validation.

Mar 2016 - Feb 2021

5 years

Software Engineer

Orion Innovation

Built internal React and Node.js dashboards for real-time system health monitoring and log visualization, surfacing service data through REST endpoints in a clean web interface.
Developed reusable React UI controls for complex 2D data rendering, applying event-driven and model-view architecture patterns directly aligned with modern frontend development.
Engineered a TypeScript data abstraction layer using the Abstract Factory pattern to decouple UI components from database implementations, enabling cleaner swapping of persistence backends without UI changes.
Improved database throughput by 40% through T-SQL query tuning and stored procedure optimization targeting high-concurrency transaction scenarios on SQL Server.
Introduced Jest and integration testing into the team’s workflow, building out test coverage that reduced production regression defects by 25%.
Authored Node.js ETL scripts to automate extraction, transformation, validation, and loading of legacy XML datasets into SQL Server, eliminating manual migration effort and improving data reliability.
Worked within Agile/Scrum delivery cycles, translating high-level requirements into detailed technical specifications, implementation plans, and verification steps for web-facing and backend service components.

Industry Experience

See where this freelancer has spent most of their professional time.

Experienced in Information Technology.

Information Technology

Business Area Experience

See which departments and functions this freelancer has contributed to most.

Experienced in Information Technology, Quality Assurance, and Product Development.

Information Technology

Quality Assurance

Product Development

Summary

Senior Fullstack Engineer with 12+ years of experience delivering scalable Node.js services, production-grade REST APIs, and data-intensive web applications across enterprise environments. Strong hands-on background in JavaScript, TypeScript, Node.js, React, and modern fullstack engineering, with practical AI/LLM workflow experience across RAG, MCP servers, agent skills, spec-driven AI development, AI verification, evaluation, and output confirmation.

Skilled at designing microservices, event-driven workflows, cloud-native deployments, async data pipelines, component-based user interfaces, and reliable database-backed systems using Docker, Kubernetes, Azure, SQL Server, PostgreSQL, Redis, and MongoDB. Known for owning complex problems end-to-end - from API contract design and backend architecture to AI-assisted delivery, performance tuning, observability, testing, CI/CD, and technical leadership.

Skills

Languages: Javascript, Typescript, Node.Js, Sql, Python
Backend: Node.Js, Nestjs, Express.Js, Fastify, Rest Api Design, Graphql, Grpc, Microservices, Websockets, Socket.Io, Typeorm, Prisma, Dependency Injection, Repository Pattern
Frontend & Ui: React, Next.Js, Redux Toolkit, Zustand, Tailwind Css, Material Ui, Component-Based Ui Architecture, Websockets, Real-Time Dashboards, Data Visualization
Cloud & Devops: Azure, Docker, Kubernetes, Ci/Cd, Github Actions, Jenkins, Azure Devops, Nginx
Data & Messaging: Kafka, Rabbitmq, Redis, Websockets, Socket.Io, Mqtt, Protocol Buffers, Async Queues, Event-Driven Architecture
Ai Engineering: Cursor, Claude Code, Github Copilot, Openai Api, Mcp Servers, Tool Calling, Rag, Agent Skills, Embeddings, Vector Search, Structured Prompts, Ai-Assisted Refactoring, Test Generation
Databases: Sql Server, Postgresql, Redis, Mongodb, Query Optimization, Partitioning, Caching
Observability & Testing: Jest, Vitest, Supertest, Playwright, Cypress, Unit & Integration Testing, Opentelemetry, Datadog, Performance Profiling
Architecture & Engineering Practices: Solid, Design Patterns, Api-First Design, Async I/O, Performance Optimization, Scalability, Agile/Scrum, Code Reviews

Languages

English

Advanced

Serbian

Intermediate

Education

Feb 2011 - Aug 2015

University of Niš

Bachelor’s Degree · Niš, Serbia

Statistics

Experience

Total positions 3

Experience in Information Technology 10.5 y

Avg length 3 y 4 m

Longest experience 4 y 11 m

Expertise

Recent roles Technical Lead, Senior Software Engineer, Software Engineer

Main industries Information Technology

Main business areas Information Technology, Quality Assurance, Product Development

Qualifications

Highest degree Bachelor

Profile

Created

June 2026

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Frequently asked questions

Have questions? Find more information here.

Where is Darko based?

Darko is based in Barič, Serbia.

What languages does Darko speak?

Darko speaks the following languages: English (Advanced), Serbian (Intermediate).

How many years of experience does Darko have?

Darko has at least 10 years of experience. During this time, Darko has worked in at least 3 different roles and for 3 different companies. The average length of individual experience is 3 years and 5 months. Note that Darko may not have shared all experience and actually has more experience.

What roles would Darko be best suited for?

Based on recent experience, Darko would be well-suited for roles such as: Technical Lead, Senior Software Engineer, Software Engineer.

What is Darko's latest experience?

Darko's most recent position is Technical Lead at Sipod.

What companies has Darko worked for in recent years?

In recent years, Darko has worked for Sipod and Axians Serbia.

Which industries is Darko most experienced in?

Darko is most experienced in industries like Information Technology.

Which business areas is Darko most experienced in?

Darko is most experienced in business areas like Information Technology, Quality Assurance, and Product Development.

Which industries has Darko worked in recently?

Darko has recently worked in industries like Information Technology.

Which business areas has Darko worked in recently?

Darko has recently worked in business areas like Information Technology, Product Development, and Quality Assurance.

What is Darko's education?

Darko holds a Bachelor from University of Niš.

What is the availability of Darko?

Darko is immediately available full-time for suitable projects.

What is the rate of Darko?

Darko's rate depends on the specific project requirements. Please use the Meet button on the profile to schedule a meeting and discuss the details.