Freelancer profile translated to English.

Description

Senior Java / Spring Boot Developer with a focus on enterprise and FinTech systems.

I spent over six years at CHECK24 Kreditkarte, most recently as Team Lead of a cross-functional engineering team with full responsibility for the entire lifecycle of post-lead components – around 20 microservices based on Spring Boot.

I was the technical contact for partner banks and responsible for integrations with over 15 banks, several KYC and scoring providers, as well as other partners.

I have extensive experience with REST, SOAP, and SFTP integrations, event-driven architectures, and am proficient in highly regulated environments with a strong focus on security and best practices.

As a freelancer, I support DACH clients with Java stacks, from security audits and infrastructure hardening to systems for the German energy market and the further development of existing platforms.

I value clean code, sustainable solutions, and long-term collaboration.

Fluent in German, English, and Croatian.

Available for project-based assignments up to 20 hours per week.

Industry field of expertise

Languages

German
Fluent
Croatian
Native or bilingual
English
Fluent

Workplace preferences

Remote only

Primarily works remotely

Freiberuflich
Freelancer Software Engineer
ENERGY AND UTILITIES
April 2025 - Today (1 year and 2 months)
Germany
• Implementation and maintenance of Spring Boot microservices handling energy market messaging and client-management workflows, including parsing and routing standardized message formats (EDIFACT and similar).
• Security reviews and hardening of Spring Security configurations, followed by targeted improvements and remediation.
• Extending tenancy model to support additional tenant types with data isolation and onboarding flows.
• Integration of backend services with React frontends and internal/external APIs
• End-to-end delivery and incident fixes.
Spring boot Backend Service Development EDIFACT Spring Security Java
CHECK24 Vergleichsportal
Software Development Team Lead
BANKING AND INSURANCE
January 2024 - August 2025 (1 year and 7 months)
Munich, Germany
- Leading a cross-functional team of software engineers
- Improving internal development processes to enhance efficiency, knowledge sharing and collaboration
- Still coding part-time while managing sprint planning and ensuring project deadlines
- Collaborating with PMs during initial specification phases, making bigger technical decisions and delegating tasks
- Managing team logistics (vacation planning, regular one-on-ones) and overseeing team development through performance reviews, salary negotiations, and candidate interviews.
IT Project Management Java External API Integration Fintech Microservices
CHECK24 Vergleichsportal
Senior Software Developer
BANKING AND INSURANCE
July 2023 - December 2023 (5 months)
Munich, Germany
- Leading technical planning and major projects from early specification stages.
- Writing and maintaining of internal and external technical documentation
- Mentoring junior colleagues and acting as a technical point of contact for partner banks.
- Monitoring system health, identifying architectural issues, and defining technical tasks.
- Spearheaded the machine learning initiative - training, deployment and monitoring of real-time prediction systems.
Java Spring Python MLflow Machine Learning