Tech lead

Sasa Fajkovic

Technical leader with a product mindset.

About me

Welcome to my personal page. You can find out more about me, my professional journey, education and skills, or read some of my publications.

Feel free to reach out over email if you have any questions or would like to discuss a potential collaboration.

If you need a copy of my CV, you can download it by clicking the button below.

PDF CV

My blog articles

View all posts »

Learn more about my thoughts and experiences. You might find an interesting thing or two.

2025: The year AI learned to work (and I still didn't write enough blog posts)

A reflection on how AI agents transformed software development in 2025, my goals for building AMOS in 2026, and why powerful tools still require human discipline.

The AI Era and Junior Developers: Progress Over Hype

How AI is transforming junior developer roles and creating new opportunities for learning and growth in software engineering

AI-Powered Dependency Management

Revolutionize your workflow by invoking AI agents to handle dependency upgrade pull requests automatically

Unsupervised CI/CD

Autonomous integration and deployment to production

Professional journey

Head of Developer Experience
Trade Republic, Berlin, DE
2022 - Present

Leading teams and deliverables across multiple domains:

Developer Experience
- AI & LLM tooling onboarding & management - being at the forefront of AI tooling enabling higher engineering throughput
- Unified CICD pipelines - cost and speed optimised solutions for fast and compliant continuous deliverables
- Self-managed, fully hosted GHA runners - 30% speed increase, 60% cost reduction
- Cost-optimization initiatives through self-hosting
- Internal developer portal - reducing product engineering time waste
Banking domain
- Customer cash balance & reservation system
- Abstract core accounts orchestration offering virtually unlimited structure and number of accounts
- Interest calculation, tax processing and payout
- Ledger book with endless subledger creation options
Timeline event aggregation
- Cash & trading transaction grouping, filtering & aggregation done on-the-fly
- Arhitecture redesign - from central aggregator to distributed
- Financial statement release process
Customer lifecycle domain
- GDPR compliant data-management - from onboarding to offboarding
- Customer screening & verification - world-wide screening and PIP check
- Authorization access management
- Document management lifecycle
- Risk assessment - multi-variant input based risk assessment system

Tech stack:

Kotlin, Spring Boot, Ktor, Vert.x
Kafka, RabbitMQ
Kubernetes, Docker
Prometheus, Grafana, Loki
AWS, Snowflake, GitHub Actions
PostgreSQL, Aurora

Engineering manager & Senior engineer
Deutsche Kreditbank AG, Berlin, DE
2020 - 2022

Managed a full-stack team (backend, frontend, QA) to ensure multiple deliveries:

New customer onboarding flows
Provisioning of 5+ mil. customers to a new debit card
Replacing legacy system with modern http REST APIs

Tech stack:

Kotlin, Spring Boot
Kubernetes, Docker
Prometheus, Grafana, Kibana
GitLab CI
PostgreSQL

Founder
Digitalni val, Zagreb, HR
2018 - 2020

Small agency offering B2B and B2C digital solutions

Proprietary system for real-time event-driven betting
Small to medium eCommerce & website development
Proprietary B2C CRM tooling
Retail office management

Tech stack:

Kotlin, Spring Boot
NodeJS, Puppeteer
Ubuntu server & Windows server
PostgreSQL

Lecturer
Algebra, Zagreb, HR
2016 - 2018

Lecture/Teacher with ECDL expertise, educating over 300 individuals

Introduction to web development - PHP, HTML, CSS, MySQL
Java programming (for backend and Android)
Microsoft Excel - ECDL Expert, Intermediate & Beginner
Microsoft Access - ECDL Expert, Intermediate & Beginner

Team lead
UniCredit group, Zagreb, HR
2016 - 2018

Leading a full stack team (backend, frontend) developers, delivering core retail banking products.

CRM tool built from scratch ensuring smooth and compliant B2C relationship
Do Not Call registry integration ensuring compliance and automated data processing
PSD2 regulation - backend implementation ensuring compliance and on-time delivery

Tech stack:

Java, Spring Boot
HTML, CSS, JS, AngularJS
Jenkins, GitLab
IBM CICS, IBM DB2

Project Manager & IT administrator
Carpe Diem, Karlovac, HR
2014 - 2016

Leading and coordinating project deliveries, ensuring on-time and within budget delivery of activities. Digitalized business flows with redundancy improving efficiency while lowering costs.