Portfolio · 2008 to Today

Dejan
Petković

End-to-end productAI · Fullstack · Cloud
Dejan Petković, smiling, in Amsterdam
That’s me. Hi.
Intro

I take products from zero to live: architecture, infrastructure, backend, frontend, mobile, and the AI/ML pipeline. Seventeen years of engineering across the full stack means I can own the entire solution, not just one layer of it.

§ 01 · About

I build the whole product.

Bio

I have spent seventeen years shipping end-to-end products, owning everything from cloud infrastructure and backend services to mobile, web, and now the AI layer that sits on top. My strength is the rare combination: deep enough in each layer to make the right architectural call, broad enough to carry a product from a blank repo to a live service customers depend on.

As a Dutch citizen and fluent speaker of English, Dutch and Serbian, I have worked extensively with Dutch 🇳🇱, American 🇺🇸 and British 🇬🇧 customers.

That breadth was earned the hard way: building cloud infrastructure and the observability stack for Liberty Global's OTT streaming platform, leading human–machine interaction work on the Amelia AI framework, architecting batch and streaming data platforms at KPN, then leading mobile and web product teams at Fertifa and Grndhouse, and today designing production AI systems for clients like Delphyr.

Building with generative AI is no longer just a learning interest. It is my day job. You can browse some of my experiments on GitHub, including agentic usage with MCP servers.

Off-hours: family, learning Dutch, strength training, and riding the kids to school in our Urban Arrow bakfiets. So gezellig. 🎉

Experience
17 yrs
Since 2008, in production
Languages
4
EN · NL · SR · DE
Companies
8
From Liberty Global to Delphyr
§ 02 · Projects & Services

Things I have built.

Selected · 2017–2026
01 · FeaturedMedical AI SaaS · Built from scratch

Delphyr

delphyr.ai

A next-generation AI platform for the medical field: secure, scalable SaaS bringing AI into real clinical workflows. Built together with the founder, I shipped Delphyr practically from scratch as the founding engineer, alongside a tiny team of one additional engineer and one data scientist. I own architecture, infrastructure, backend, mobile, and the AI/ML pipeline end to end.

Visit Delphyr
Team
1 + 3
Founder + me + eng + DS
Stack
TS / Py
NestJS · React Native
Scope
E2E
Infra · model · UI
What I built
· Cloud-native architecture & CI/CD
· GenAI fine-tuning & eval pipeline
· Observability: Grafana · Tempo · ES
· React / React Native frontends
· NestJS / Python backends
· Compliance & data security model
02SaaS · Finance

Biller

biller.elands.studio

Professional invoicing for freelancers. Create, send, and track invoices in seconds. One-time purchase, no subscriptions.

Visit Biller
03Civic · Dutch market

Bouwen

bouwen.elands.studio

Renovation project communication for the Dutch market. Print a QR code for your window and let neighbours follow your renovation in real time.

Visit Bouwen
04Tax · Calculator

2e-woning.nl

2e-woning.nl

Box 3 tax calculator: easily calculate your tax for a second home and other investments. Built for the Dutch market.

Visit 2e-woning.nl
05LLM · WhatsApp bot

brAIn

github.com/dexpetkovic/brAIn-demo

WhatsApp AI assistant built with NestJS and Google Gemini. Handles webhooks, stores memories, creates calendar events, and provides automated replies.

View on GitHub
§ 03 · Skills

The toolbox.

Programming Languages

TypeScriptPythonScalaGroovyJava

Frameworks

Next.jsFastAPILangWatchReact NativeReactStrapiSpringFlaskpandasAkkaProtobuf / AvroCamelJenkins (CI/CD)Terraform (IaC)Git

Software Platforms

AWSAzureMLOps toolingKubernetesDockerKafkaSpark / DatabricksFlinkMuleSoftapache / nginxLinuxWireshark

Spoken Languages

English · ProficientDutch · Proficient (NT2)Serbian · NativeGerman · Intermediate
§ 04 · Experience

Seventeen years, compounded.

2025Jan 2025 to PresentActive

Founder & AI Engineer

Elands AI

Elands AI designs and delivers intelligent systems tailored to our clients' needs. We work primarily with startups and small companies, specialising in turnkey AI platforms and ML systems, handling everything from architecture to production deployment.

  • Designing and delivering custom LLM-based applications and AI platforms for clients
  • Building MLOps infrastructure and data pipelines from scratch to production
  • Working across the full stack with TypeScript and Python, combining cloud-native engineering with cutting-edge AI capabilities
  • Shipping robust, scalable products that deliver real business value
2025Jul 2025 to PresentActive

Founding AI Engineer

Delphyr B.V. · Medical AI SaaS

Leading design and development of a next-gen AI platform built specifically for the medical field: a secure, scalable SaaS that brings AI into real clinical workflows, from hospitals to GP practices, without compromising on usability, privacy, or compliance.

  • Technical depth & architecture: scalable AI/data platforms, system integrations, trade-offs between performance, cost, and complexity
  • AI/ML expertise: GenAI end-to-end, covering model development, fine-tuning, evaluation, and deployment
  • Full-stack: frontend/mobile (React / React Native), backend (Node.js, Python, NestJS), infrastructure (cloud, containers, tracing/logging)
  • Data & MLOps: production pipelines with Grafana, Tempo, Elasticsearch
  • Collaboration: mentoring, defining best practices, making technical decisions transparent
2024Sep 2024 to Jul 2025

Expert Software Engineer

Totally Gifts · Greenfield gift redemption platform

Helping build a new gift redemption platform from scratch with a modern tech stack.

  • Applied GenAI to generate images and video for the platform (Replicate, HuggingFace, OpenAI)
  • Next.js, TailwindCSS, Clerk, Sentry, NestJS, PostgreSQL, Docker, AWS
  • Event-driven architecture for capturing and processing gift card events in real time
  • Contributed across the stack with a cross-functional team of three engineers, a designer, and a product owner
2023Nov 2023 to Sep 2024

Lead Fullstack Software Engineer

Grndhouse · On-demand strength training

Team lead managing 5 backend & frontend developers. Streamlined feature development for the MVP across video streaming, payment processing, and user management.

  • Architected and engineered solutions in React Native, Node.js and AWS
  • Mentored junior developers, resolved blockers, ensured timely delivery
  • Tooling: Sentry, RevenueCat, Mixpanel
  • Expo for App lifecycle and deployments, with and without App Store / Play Store releases
2021Dec 2021 to Nov 2023

Fullstack Software Engineer

Fertifa · Reproductive healthcare

IC and later team lead managing 5 backend & frontend developers at Europe's most comprehensive reproductive healthcare provider.

  • Engineered solutions in React Native, Node.js and AWS
  • Tooling: Sentry, Strapi, Google Analytics, Meta Pixel, Drip, Amplitude
  • Manually managed app lifecycle and deployments
2018May 2018 to Dec 2021

Senior Software Engineer, Batch & Streaming Data

KPN Technium B.V.

A deep dive into data platforms and the intricacies of transformation to a data-driven company.

  • Senior engineer on an ETL automation framework on Azure, Hadoop/Kafka, automated with Terraform
  • Rendering framework built with Python, Flask, SQLAlchemy
  • Led part of story mapping for migrating on-prem data services to Azure / AKS
  • Distributed event-sourcing application for real-time analysis of the KPN customer journey
  • Scala / Akka / Alpakka microservices and Flink applications
  • Fully automated CI/CD, monitoring, and alerting
2017Feb 2017 to May 2018

Software Engineer, Cognitive Implementation

IPsoft B.V. · Automated Vodafone customer service with Amelia AI

Where I learned machine learning, prompt engineering and how to make data-driven decisions. Led a team that automated Vodafone's customer service agents using the Amelia AI framework.

  • Technical lead of a 3-member agile team building human-machine interaction on Amelia
  • Hands-on development, code reviews, mentoring, Scrum rituals
  • Managed business requirements and solution architecture
  • Stack: Groovy / Python / Java · Kafka · Camel · Mule · Elasticsearch · Spring · Grails · Docker
  • Data analysis with Pandas / Jupyter, d3.js for visualisation
2012Jun 2012 to Jan 2017

Senior System Engineer

Liberty Global B.V. · OTT streaming (Ziggo Go)

Member of Liberty Global's OTT streaming solution architecture & engineering team, combining software and system engineering on complex infrastructure.

  • Developed AWS (micro)services infrastructure, CDN content delivery, Adobe AEM and their integrations
  • Data analysis with Jupyter, Wireshark, Conviva, Omniture
  • Code reviews and overall system troubleshooting
  • Deep web/backend, streaming, HA scalable infrastructure, AWS, and network protocol experience
For recruiters

Download the CV.

Grab the PDF or send a message.

Download CV (PDF)↓Send a message
§ 05 · Contact

Say hello.

Want to get in touch? Send a message about a project, a role, or just to say hi.