Bojan Gajic

Providing software architecture, backend engineering, and IT consulting services for banking, fintech, telecom, and enterprise clients. Focused on designing scalable distributed systems, modern integration platforms, and secure API-driven architectures. – Designing and delivering Java/Spring Boot microservices and event-driven platforms – Building integration solutions between core banking systems, external providers, and enterprise applications – Supporting full delivery lifecycle: requirements analysis, architecture, implementation, testing, deployment, and production rollout – Designing REST APIs, Kafka-based integrations, and high-throughput backend services – Helping organizations modernize legacy systems toward cloud-native and microservice-based architectures – Providing technical leadership, architecture guidance, mentoring, and delivery coordination across distributed teams – Applying AI-assisted development workflows to improve engineering productivity, documentation, and delivery efficiency Specialized in: – Banking and financial services platforms – Avaloq integration and customization environments – Enterprise integration and API architecture – Event-driven systems and distributed backend platforms – Secure authentication and authorization (OAuth2/OIDC, Keycloak, JWT) Technology focus: Java, Spring Boot, Spring Cloud, Kafka, REST APIs, Docker, Kubernetes, PostgreSQL, Oracle, GitLab CI/CD, Keycloak, Microservices Architecture, DDD, Distributed Systems. Available for remote consulting and international engagements.

• Designed and delivered a modern integration layer (Integration Lab) acting as a strategic middleware between Avaloq core banking and satellite systems (Frontend, Financial Instruments Master - FMA and external providers), enabling standardised data access, orchestration, and digital service delivery, while supporting the gradual modernisation of the bank’s IT landscape without disrupting existing operations. • Enabled digital banking and regulatory use cases by exposing business oriented APIs and near-real-time event streams, abstracting Avaloq’s complex data model and allowing client-facing, employee-facing, and third-party applications to consume data in a consistent, secure, and auditable manner. • Designed and implemented read, write, and streaming services supporting core banking operations such as payments, stock exchange orders (STEX), and securities data, including synchronous request/ response flows and Kafka-based event propagation for near-real-time system integration. • Architected and delivered a scalable, high-throughput microservices platform (Java 21, Spring Boot 3.x) combining REST APIs, scheduled and batch processing, and a DDD-based, extensible service architecture to handle large volumes of transactional and securities reference data, improving data freshness, traceability, and readiness for risk, compliance, and ESG-related use cases. • Established a secure and production-grade platform foundation, including NGINX-based API gateway, JWT authentication services (OAuth2/OIDC with Keycloak), and cloud-native DevOps automation (GitLab CI/CD, Docker, Kubernetes, automated testing), ensuring secureby- default access, regulatory compliance, operational resilience, and scalable delivery in a banking environment.

• Core member of an Agile payments team, developing and supporting a central payments framework used across E-Banking, Mobile Banking, and Core Banking platforms. • Designed and implemented payment processing components for multiple payment types, ensuring transactional integrity, scalability, and regulatory compliance in high-volume banking systems. • Held technical ownership of the QR payment scanner, covering backend services, integrations, and frontend components (jQuery-based UI), acting as the primary technical contact within the payments scrum team. • Led the transition from monolithic legacy systems to microservice-oriented modules, improving maintainability, deployment flexibility, and system scalability. • Applied domain-driven design (DDD) using Java, Spring Framework, Hibernate, and Oracle DB, with RESTful and asynchronous integrations (RabbitMQ), supported by CI/CD pipelines and containerized environments (Jenkins, Docker, Kubernetes, Rancher).

Document and develop new architecture in a process of migrating legacy applications into (Spring Cloud based) microservice architecture. Document and develop new architecture in a process of upgrading business model into Digital banking software provider. Provide architectural blueprints and technical leadership to IT team. Evaluate and recommend tools, technologies and processes. Create API documentation in swaggerhub. Development and configuration of Spring Boot and Spring Cloud components (Config server, API Gateway, Service registry, Circuit Breaker, Tracing)... Development and configuration of Keycloak Identity and Access Management server. Integration with SonarQube code analysis and Quality Gate settings. Integration with Kafka platform. AWS integration. Troubleshoot code level problems and CI/CD pipeline issues.

• Designed and developed high-availability Packaging REST API microservices for an airline ticketing and offers platform, supporting complex fare, bundle, and ancillary product packaging workflows. • Built secure, scalable APIs using Java 8 and Spring Boot, implementing JWT-based authentication and authorization with Spring Security and Auth0, and producing consumer-ready API contracts via Swagger/OpenAPI. • Led the integration of new microservices with existing Datalex systems, ensuring backward compatibility, data consistency, and minimal impact on live airline operations. • Acted as Technical Team Lead for a team of 5 engineers, providing architectural guidance, code reviews, mentoring, and delivery ownership within agreed quality, scope, and timelines. • Established automated and performance testing practices (Gatling), validating system behavior under high concurrency and peak booking traffic. • Worked in a Scrum-based Agile environment, collaborating closely with product owners, QA, and distributed teams to deliver incremental value.

Design and development of Hotel Event Design back-end system. (Java, Spring Framework, Thymeleaf template engine, Hibernate, JAX-RS, JQuery, MySQL DB, Tomcat Server). Agile software development including Scrum methodology and Atlassian tools stack.

• Progressed from Associate Software Engineer to Lead Engineer and ultimately Senior Engineer / Project Manager, taking increasing responsibility for system design, integration architecture, team leadership, and delivery ownership across enterprise telecom platforms. • Started with hands-on development of Java web and portal applications (JBoss Portal, JSP, Servlets), reporting and analytics solutions, and database programming (Oracle, PostgreSQL), building a strong foundation in enterprise Java and relational data modeling. • Advanced to full-stack and integration leadership, designing and implementing SOA-based and multi-tier systems for portals, web shops, product catalogs, billing, loyalty, and order management, integrating CRM, Inventory, Billing, and Back Office systems via REST and SOAP (JAX-WS, Apache Axis). • Took ownership of system architecture and platform initiatives, including Alfresco-based document management, payment and loyalty services, and tariff management applications, applying clean layering, reuse, and service-oriented principles. • Assumed technical leadership and project management responsibilities for multi-million € enterprise programs, such as Convergent Billing and Real-Time Billing Enabler, managing teams of 5–20 engineers, performing business analysis, prototyping, risk management, and senior-stakeholder communication using Agile and Waterfall methodologies.