I build data platforms, AI tools, and useful web products that actually ship.

Dejan Stajic - data engineering, applied AI, automation, and product-focused debugging.

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Dejan Stajic - Data Engineer

About Me

I'm Dejan Stajic, a data and applied AI engineer based in Orlando, FL. I build systems that turn messy workflows into inspectable software: pipelines, dashboards, AI helpers, local-business automations, and public web apps. My working style is simple: prove the real state, automate the repeatable part, and keep the result easy to operate.

Experience Highlights

  • Builds data platforms, internal tools, and AI-assisted workflows that can be inspected end to end
  • Ships public web apps and prototypes quickly, then tightens them with live browser proof
  • Works across data engineering, applied AI, local-business automation, and product-focused UI
  • Prefers evidence-first debugging: reproduce the failure, isolate the layer, prove the fix
  • Maintains a current project portfolio with live demos rather than static descriptions only

Core Values

Clarity over Complexity

Every solution must be transparent—no hidden steps, no black boxes.

Automation with Purpose

If a task repeats more than twice, I automate it.

Truth-First Approach

I validate assumptions with data; if evidence is lacking, I generate and test hypotheses.

Operational Proof

A deployment, link, or metric is not real until the exact surface has been checked.

Services & Expertise

What I build across data, AI, automation, and product work

Data Pipeline Architecture

Design, implement, and optimize data workflows using Apache Airflow, dbt, and SQL.

  • • Zero-downtime schema migrations
  • • Fault-tolerant scheduling
  • • Performance optimization

Database Development

PostgreSQL cluster configuration and maintenance with real-time analytics.

  • • Cluster configuration
  • • Performance tuning
  • • Materialized views

AI/ML Experimentation

Reinforcement learning research with Monte Carlo, PPO, and curriculum learning.

  • • MLflow experiment tracking
  • • Distributed RL training
  • • Ray cluster deployment

Web Application Development

End-to-end development with React front-end and FastAPI back-end.

  • • Data-centric dashboards
  • • Docker + Kubernetes
  • • Scalable deployments

DevOps & CI/CD

GitOps workflows, automated testing, and continuous delivery.

  • • Infrastructure as Code
  • • Terraform deployments
  • • Reproducible environments

Problem Solving

First-principles approach to complex data challenges and system optimization.

  • • Root cause analysis
  • • Process automation
  • • Scalable solutions

Key Projects

Live demos first, with concise notes on what each project proves

Local IPTV EPG

Live Demo

Local-first TV guide and playlist metadata mapper for IPTV EPG data.

Live Demo

Built as a practical guide browser: country selection, channel search, current schedule, timeline views, translation fallback, favorites, and M3U tvg-id repair helpers.

Tech Stack

PythonSvelte-style UIEPG XMLM3U parsingVercel
Case Notes: Hosted as a portfolio-safe static demo. The local version handles EPG parsing through a localhost server and does not provide streams.

SnapBadge

Live Demo

Social photo-sharing experiment organized around collectible badges.

Live Demo

A consumer web app focused on visual organization, lightweight social mechanics, and fast public browsing.

Tech Stack

Web appProduct designMedia UX
Case Notes: Shows product thinking, public deployment, and end-to-end app polish.

Osceola Sod

Live Client Site

Local service-business website rebuilt for SEO, lead capture, and operational independence.

Live Demo

Focused on practical business outcomes: clearer service pages, conversion paths, vendor-lock-in reduction, and ad/SEO readiness.

Tech Stack

SEOLocal businessAutomationWeb
Case Notes: Public client-facing work. Useful proof of shipping for a non-technical business audience.

Debugger

Live Demo

Educational debugging platform for developers who want to get better at diagnosing failures.

Live Demo

Turns debugging practice into structured lessons and examples instead of vague trial-and-error.

Tech Stack

TypeScriptEducationDebugging UX
Case Notes: Connects directly to my core working style: reproduce, isolate, prove, then fix.

Horseplay

Live Demo

Remote-friendly web version of the basketball game HORSE.

Live Demo

A lightweight multiplayer-style game concept for friends playing asynchronously or remotely.

Tech Stack

Web gameInteraction designVercel
Case Notes: Demonstrates quick productization of a familiar real-world game loop.

Casetify Chatbot

Live Demo

Client-style chatbot prototype for inventory, support, and booking workflows.

Live Demo

Built around the common small-business need to consolidate repetitive customer interactions into one assistant.

Tech Stack

PythonChatbotWorkflow automation
Case Notes: Shows applied AI workflow design around practical business operations.

Yahtzee

Live Demo

A redesigned Yahtzee-inspired game with quality-of-life improvements and roguelike ideas.

Live Demo

A small interactive project focused on game feel, rule clarity, and replayability.

Tech Stack

TypeScriptGame designInteractive UI
Case Notes: Also connects to my broader interest in RL/game systems without making unsupported performance claims.

Skills & Tools

Languages

PythonSQLBashJavaScript

Data Engineering

Apache AirflowdbtPostgreSQLRedisAWSDockerKubernetes

Machine Learning

Ray RLlibTensorFlowPyTorchMLflowscikit-learnPandas

Web & DevOps

FastAPIReactTailwind CSSGitHub ActionsTerraform

Monitoring

PrometheusGrafanaELK Stack

Education

B.S. Computer Science, UCF (2018)

Focused on production data systems, applied AI, and practical automation.

Current public work is linked above as live demos.

Portfolio Proof Notes

Project cards link to working public demos wherever possible, with concise case notes for context.
✓
Live demos first
Current portfolio standard
This page avoids unsupported user counts, fabricated testimonials, and unverifiable impact metrics.
✓
No inflated claims
Current portfolio standard
The work spans data systems, AI helpers, games, local-business sites, and polished utility apps.
✓
Practical range
Current portfolio standard

Let's Connect

Ready to solve your toughest data problems together?

dejan@datapilot.us
Orlando, FL (open to remote)
GitHub
"Let's solve your toughest data problems together. No jargon, no fluff—just results."
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