10/20/2026 updated
100 % available
Senior Java / Spring Boot & Angular Engineer
Nitra, Slovakia
Only remote
Master's degree (Mgr.), Teaching of Mathematics and PhysicsAbout me
Senior Java full-stack freelancer (20+ yrs), 100% remote via Lubisoft s.r.o. (SK, EU VAT). Legacy modernisation: Spring Boot 2→3→4, Java 21, Oracle→PostgreSQL, Keycloak, Angular 9→20, AWS. Ex-SAP; clients: Deutsche Telekom, Swiss Re, T-Mobile. Projektsprache Englisch, Deutsch B1 passiv.
AI AgentsJava (Programming Language)Spring SecurityDB2 SQLGradleJava ArchitecturesSpring FrameworkPython (Programming Language)PostgreSQLApache MavenMySQLAngular 2+SAP HANAAngular MaterialSpring Cloud
Java & Spring Boot Backend Development
Expertise in Java 8 through 21 and Spring Boot 2/3/4, including Spring Security, Spring Cloud, Spring WebFlux, Spring Data JPA, Hibernate, REST/OpenAPI, SOAP, and Camunda BPM. Extensive experience delivering enterprise backend systems across telecom, banking, insurance, and government sectors.
Angular & Frontend Engineering
Proficiency in Angular from AngularJS up to version 20, TypeScript, RxJS, NgRx, Angular Material, PrimeNG, Nx monorepo, React, and React Native. Track record of major Angular version migrations and training Java developers in Angular.
Cloud & DevOps
Hands-on experience with AWS (ECR, EC2, Lambda, Aurora, S3, DynamoDB, CloudWatch, IAM, CloudFormation), GCP, Docker, Kubernetes, Helm, OpenShift, Rancher, Terraform, GitLab CI/CD, ArgoCD, TeamCity, Jenkins, and Azure DevOps.
Microservice & Event-Driven Architecture
Design and implementation of microservice and event-driven architectures using RabbitMQ, ActiveMQ, Spring Cloud, and Quarkus. Experience migrating legacy monoliths to modern distributed systems.
Database Technologies
Broad knowledge of relational and NoSQL databases including PostgreSQL, Oracle, MySQL, AWS Aurora, DynamoDB, DB2, MS SQL, Trino, Liquibase, and Flyway. Experience with Oracle to PostgreSQL migrations.
Security & Authentication
Implementation of security solutions using Keycloak, OAuth2/OIDC, JWT, LDAP, MS Active Directory, and vulnerability and CVE remediation with ORCA scanner.
Testing & Quality Assurance
Application of testing frameworks and tools including JUnit, Mockito, TestContainers, WireMock, Cucumber, Selenium, MapStruct, Lombok, JHipster, and Maven.
GoLang & Python Development
Development experience with GoLang and Python, including backend rewrites and AWS Lambda functions for own products.
Application Modernisation
Specialisation in Spring Boot upgrades, Angular major-version migrations, Oracle to PostgreSQL migrations, and LDAP to Keycloak (OAuth2/OIDC) transitions.
Expertise in Java 8 through 21 and Spring Boot 2/3/4, including Spring Security, Spring Cloud, Spring WebFlux, Spring Data JPA, Hibernate, REST/OpenAPI, SOAP, and Camunda BPM. Extensive experience delivering enterprise backend systems across telecom, banking, insurance, and government sectors.
Angular & Frontend Engineering
Proficiency in Angular from AngularJS up to version 20, TypeScript, RxJS, NgRx, Angular Material, PrimeNG, Nx monorepo, React, and React Native. Track record of major Angular version migrations and training Java developers in Angular.
Cloud & DevOps
Hands-on experience with AWS (ECR, EC2, Lambda, Aurora, S3, DynamoDB, CloudWatch, IAM, CloudFormation), GCP, Docker, Kubernetes, Helm, OpenShift, Rancher, Terraform, GitLab CI/CD, ArgoCD, TeamCity, Jenkins, and Azure DevOps.
Microservice & Event-Driven Architecture
Design and implementation of microservice and event-driven architectures using RabbitMQ, ActiveMQ, Spring Cloud, and Quarkus. Experience migrating legacy monoliths to modern distributed systems.
Database Technologies
Broad knowledge of relational and NoSQL databases including PostgreSQL, Oracle, MySQL, AWS Aurora, DynamoDB, DB2, MS SQL, Trino, Liquibase, and Flyway. Experience with Oracle to PostgreSQL migrations.
Security & Authentication
Implementation of security solutions using Keycloak, OAuth2/OIDC, JWT, LDAP, MS Active Directory, and vulnerability and CVE remediation with ORCA scanner.
Testing & Quality Assurance
Application of testing frameworks and tools including JUnit, Mockito, TestContainers, WireMock, Cucumber, Selenium, MapStruct, Lombok, JHipster, and Maven.
GoLang & Python Development
Development experience with GoLang and Python, including backend rewrites and AWS Lambda functions for own products.
Application Modernisation
Specialisation in Spring Boot upgrades, Angular major-version migrations, Oracle to PostgreSQL migrations, and LDAP to Keycloak (OAuth2/OIDC) transitions.
Experience
Professional experience10+ years
Freelancer since2010
Languages
GermanGoodEnglishFluentSlovakNative speakerCzechFluent
Project history
Founded and operates Lubisoft s.r.o. as a B2B contracting vehicle, delivering senior fullstack engineering services remotely across Europe.
At Tatra banka: led cloud migration of the internal ILLP Calculator banking application to AWS, upgraded Spring Boot to v3 and migrated Angular 9 to 20, migrated the database from Oracle to PostgreSQL including distributed locking for scheduled jobs, and moved authentication from LDAP to Keycloak (OAuth2/OIDC) while remediating ORCA vulnerabilities. At T-Mobile Polska: migrated legacy Java microservices from Spring Boot 2.7 to 3.5 and 4.1, fixed CVEs in pom.xml and base Docker images through ArgoCD and GitLab CI/CD.
Analysed a legacy news portal (C++, Java 1.x-17, Swing, Liferay Portlets, RMI, Solr) and designed the GCP modernisation target using Java 21, Quarkus, Vue.js/Nuxt.js, PostgreSQL, Docker, and Kubernetes.