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Freelance Senior Backend Engineer · Java & Kotlin

Modernizing and evolving business-critical backend systems safely.

I help companies with complex Java and Kotlin systems, from new backend services and APIs to modernizing existing applications and integrations.

Java · Kotlin · Spring Boot · Jakarta EE · APIs · Microservices

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20+ years of experience · Banking · E-commerce · Healthcare · Public sector

Remote-first · On-site kick-offs and workshops when useful

Experience from complex projects across banking, healthcare, public services, e-commerce, and digital platforms.

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What I’m hired for

Backend Engineering

Building and evolving reliable Java and Kotlin backend services, including APIs, persistence, testing, and production delivery.

Modernization

Safely evolving existing Java systems through platform and framework upgrades, Java EE to Jakarta EE migrations, persistence modernization, and improved testability.

Integrations

Reliable interfaces and data flows between internal and external systems using APIs, messaging, and traceable operational processes.

A strong fit when …

  • a business-critical Java application needs modernization
  • a team needs experienced Java or Kotlin backend support
  • Java, framework, or application-server upgrades are approaching
  • APIs, data flows, or integrations need stabilization
  • technical change must happen while ongoing delivery and operations continue
  • complex production issues, weak test coverage, or hard-to-maintain structures slow the team down

Selected project experience

Modernized a business-critical Java application

Migrating from Java 11 to Java 21, Java EE 8 to Jakarta EE 10, and EJB 2 persistence to JPA, supported by stronger automated testing and reproducible database migrations.

Java 21 · Jakarta EE 10 · JPA · Liquibase · JUnit

Built a scalable retail-media platform

Developing distributed Kotlin and Spring Boot services, internal and external REST APIs, data workflows, and cloud infrastructure for an integrated self-service platform.

Kotlin · Spring Boot · REST · AWS · Kubernetes · Terraform

Evolved a business-critical banking application

Feature delivery, major-version upgrades, integrations, database migrations, automated testing, and build/deployment support in a regulated environment.

Java · Spring · Hibernate · Oracle · REST/SOAP · CI/CD

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What you can expect when working with me

Quickly productive in existing systems

More than 20 years of experience make it easier to understand complex codebases and domains quickly.

Technical ownership, not ticket processing

Clear decisions, pragmatic implementation, and attention to maintainability, testing, and operations.

Experience in critical environments

Projects across banking, healthcare, public services, e-commerce, and digital platforms.

Direct collaboration

No agency handoffs: you communicate directly with me, and I handle the implementation.

Working together

Available for long-term freelance backend engagements as well as clearly scoped modernization, architecture, and integration assignments. Remote-first, with on-site kick-offs, workshops, or occasional meetings when useful.

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