Vincent Vercauteren

Freelance · Senior Java backend developer · Belgium

Reliable Java backends, built faster with AI.

12 years of Java and Spring, from critical payment systems at the National Bank of Belgium to integration platforms in the public sector. I use AI every day to deliver more, without lowering the bar on quality.

Get in touch Download my CV (PDF)
Available for freelance missions · Brussels, Walloon Brabant or remote
Portrait of Vincent Vercauteren
12 yrsof Java & Spring backend
7 yrson payment systems at the National Bank of Belgium
8 teamsserved by the integration facade I maintain
4 daysto migrate 5 projects to Spring Boot 4, zero incidents

~/services

What I can do for your team

Backend missions where reliability matters, in teams that want to move faster with AI.

REST APIs and microservices

Design and development of Java / Spring Boot services, with clear contracts (OpenAPI) and solid tests.

Spring Boot · OpenAPI · REST

Framework migrations

Spring Boot 3 → 4, Java upgrades, legacy code: methodical migrations without service disruption.

Jakarta EE 11 · Jackson 3 · Java 25

Integration and messaging

Integration layers that shield business teams from third-party products, with reliable asynchronous messaging.

RabbitMQ · AMQP · IBM MQ

AI features in Java applications

RAG over your documents, data extraction from PDFs, LLM integration with cost and privacy under control.

Spring AI · pgvector · Claude

CI/CD and delivery

Pipelines that build, test and deploy your services, from commit to production.

Azure DevOps · OpenShift · Docker

AI-assisted development

Daily use of Claude Code for code, tests and reviews, always with human verification before anything ships.

Claude Code · code review

~/experience

Experience

From banking to the public sector, systems that other teams depend on.

  1. Senior Java Backend Developer · Freelance

    Oct 2023 – now

    ONEM (National Employment Office) · via Oliver James

    • Built and maintain an integration facade used by 8 business teams, implementing the vendor's mandatory contracts behind a stable API.
    • Absorbed a breaking change from the vendor inside the facade, with no impact on any consuming team.
    • Migrated 5 projects from Spring Boot 3 to 4 in about four days, with no production incident.
    • Maintain and evolve Azure DevOps CI/CD pipelines deploying 5–6 services to OpenShift.
    Java 21Spring Boot 4Spring AMQPRabbitMQOpenAPIAzure DevOpsOpenShiftClaude Code

  2. Fullstack Engineer · Consultant

    2022 – 2023

    Belgian Federal Public Service Finance · via Extia

    • Contributed to the move from a monolithic core to microservices on Docker and Kubernetes.
    • Delivered features across the Angular front end and Java back end, and coached junior developers.
    Java 11SpringAngularDockerKubernetesDB2

  3. Java Software Engineer → Technical Owner

    2015 – 2022

    National Bank of Belgium

    • Owned the interface between the cash management and payment systems: architecture, development and production releases.
    • Kept it reliable for hundreds of high-value interbank transactions per day, including daily cash deposits from commercial banks.
    • Designed REST APIs with custom Spring Security, built extensive test coverage and led framework upgrades on legacy code.
    Java 8SpringHibernateIBM MQOracleCucumber

  4. Software Engineer

    2014 – 2015

    Vecturis

    • Railway management software: a C# desktop application and a Node.js back end with MongoDB.

~/projects

AI projects

Two Java applications built around LLMs: one to understand the mechanics, one to industrialise them.

home-planner in progress

Self-hosted Spring Boot 4 application that tracks home maintenance and answers questions over uploaded manuals.

  • RAG pipeline with Spring AI 2.0 and PostgreSQL + pgvector; Claude for answers, under a monthly cost cap.
  • Local multilingual embeddings (ONNX): documents are indexed on the server, only relevant chunks reach the LLM.
  • Every technical choice recorded in Architecture Decision Records.
  • Built with Claude Code under strict guardrails: Testcontainers, property-based tests, coverage thresholds.

Private repository, access on request.

accounting-assistant

Java / Spring application that sends invoices and receipts (PDF) to an LLM and extracts structured accounting data.

  • Built on direct API calls, without LangChain4j or Spring AI, to master the underlying mechanics.
View the code on GitHub →

~/skills

Skills and training

backend

Java 8–25Spring Boot 4Spring SecuritySpring AMQPHibernate / JPARESTOpenAPIMicroservices

ai

Claude CodeAnthropic APISpring AIRAGEmbeddingspgvectorStructured output

messaging & data

RabbitMQIBM MQPostgreSQLOracleDB2Flyway

ci/cd & cloud

Azure DevOpsOpenShiftDockerKubernetesMavenGradleGit

testing

JUnitCucumberTestcontainersWireMock

frontend (secondary)

AngularReactTypeScript
Anthropic AcademyClaude 101 · Claude Code 101 · Claude Code in Action · 2026
Devoxx BelgiumJava and AI conference · 2026
Bachelor in Business ComputingInstitut Paul Lambin, Brussels · 2013