Freelance engineer & coach · Berchem, BE

Olivier Cappelle

Senior Java / Spring engineer and technical coach - ten years building backend systems and the teams around them. Freelance since 2023. Now going deep on agentic engineering: shipping production software with AI, not vibe-coded demos.

What I do
Backend & platform engineering

Java, Spring, Kotlin. Microservices, event-driven systems, Kubernetes on Azure and AWS. Architecture that survives contact with production.

Technical coaching & lead

Team lead, tech lead, trainer. I work Socratically - understand what you are trying to do, then fill the gaps. Juniors to seniors.

Agentic engineering

Claude Code, multi-agent workflows, AI-assisted delivery. Production-ready output with evals and guardrails - not slop.

Current focus
AI & agentic engineering

Outside client work I go deep on agentic engineering - building production software with AI, not vibe-coded demos. Hands-on across the current frontier of coding tools, context engineering and multi-agent workflows.

Claude Code
Slash CommandsCheckpointsMCPSkillsPluginsHooksSub-agentsRalph loops
Tools
CursorGitHub CopilotChatGPT CodexAntigravityOpenCodeAmpCoworkOpenClawClaude Agent SDK
Context & workflows
CLAUDE.md / AGENTS.mdContext engineeringMulti-agent workflowsClaude Agent TeamsGSDGas TownSandboxes
Experience
Belfius2025 - now

Senior Java/Spring developer - Risk / Compliance / Audit platform

Feature development and bug-fixing on the management platform for Risk, Compliance and Audit, plus DevOps and scripting work to keep delivery running smoothly.

Spring BootAzure StackAzure PipelinesDockerKubernetesRESTRedisELKMavenPowerShellBash
  • Feature development and bug-fixing on the Risk / Compliance / Audit platform
  • DevOps tasks and scripting in PowerShell and Bash
Corilus2023 - 25

Senior fullstack Java developer - CareConnect Nurse

Built and maintained the daily-visit and billing web app used by nurses and care workers. Technical analysis, improvements and bug-fixing, plus facilitating meetings and coaching junior and medior developers.

Spring BootSpring CloudReactKafkaAzureDockerKubernetesArgoCDELKGrafanaSonarCloudNexusApache SupersetPlaywright
  • Technical analysis and improvements on the daily-visit and billing flows
  • Set up knowledge-sharing sessions and a hackathon for the team
  • Coached junior and medior developers
  • Spring Cloud data-flow, circuit-breaker and Prometheus in production
DPG Media2023

Senior Spring developer - Streamz / VTM GO

Onboarding flow and account / subscription management for Streamz and VTM GO. Ramped into Kotlin and integrated third-party user-management and subscription providers.

KotlinSpring BootAWSKubernetesGradleRESTChargebeeAdyenStripe
  • Ramped into Kotlin and delivered on Spring Boot / AWS
  • Integrated user-management and subscription providers (Chargebee, Adyen, Stripe)
Inetum-Realdolmen2015 - 23

In-house: Java Community, people & technical lead, trainer, internal projects

Java Community Lead2022 - 23

Building and running the Java Community

Built out and ran the Java Community: the training offer, the trainers behind it, technical screening and the conference presence. Owned the acADDemICT junior track and worked closely with account managers, resource officers and people managers to match junior consultants to client assignments.

JavaSpringAngular
  • Owned the acADDemICT track: a three-month junior-to-first-assignment programme
  • Fine-tuned the training offer to market / consultant / company demand
  • Found and supported trainers in building course content; followed up planning
  • Technical screener for new hires
  • Organised the Devoxx booth and coordinated group trips to Devoxx and Spring I/O
  • Took on presales and sales to match junior consultants to client assignments
  • Supported reskilling people into Java and their personal development goals
Team Lead2019 - 22

People lead for Java consultants

Responsible for the Java consultants at Inetum-Realdolmen: their integration into the company, their growth and their wellbeing. From 1-on-1s and personal development to approving time and leave, and guiding people through burnout and internal mobility.

  • Helped new consultants integrate into the company
  • 1-on-1s, personal development conversations and goal-setting
  • Followed up and approved time registration and leave
  • Supported people through mental-health struggles
  • Guided consultants before, during and after burnout
  • Guided internal mobility moves
Technical Coach2016 - 23

Coaching interns and junior starters

Technical and functional coaching of interns and young starters across internal projects, mostly Spring but also JEE. Worked out architectures and supported implementation, ran technical code reviews, and guided internship and bachelor-thesis projects end to end - including how to build and give a presentation.

SpringJEEAngularElectronJPAJSFHibernatePostgreSQLJavaGitLab
  • Technical and functional coaching on internal projects (mostly Spring, some JEE)
  • Worked out architecture and supported implementation
  • Ran technical code reviews
  • Internship coaching (spring 2017 & 2018): analysis and dev in Spring, Angular, Electron
  • Bachelor-thesis coaching (2017): Android development and shaping the research question
  • Coached on building and delivering presentations
Trainer2015 - 23

Internal trainings, workshops and talks

Nearly a decade of internal trainings, workshops and conference-style talks - mostly Spring, testing and ways of working. From a Java Community Conference talk in 2015 to multi-day trainings on testing, Git and Agile. The full catalogue:

SpringJavaGitGitLabHibernateFlywayMaven
Testing, end to end2018 - 22

Unit, service, contract and e2e/Selenium testing, and the libraries to write each: JUnit, AssertJ, Hamcrest, REST Assured. Later a three-day training and a TDD deep dive.

Spring in practice2018 - 22

Best practices, exception handling, reactive programming, declarative Feign web clients, and Code-First vs DB-First with Flyway migrations.

Git & GitLab @ FOD BOSA2019

Two-day training on Git, Git workflows and the GitLab admin console, plus helping the team pick the right workflow.

Agile ways of working2019

Workshop on Agile, Scrum, Kanban and user-story mapping.

Clean code for students2022

Workshop on fighting nesting and spaghetti code in a real codebase.

Learning & development vision2023

Talk on the why / what / how of L&D, plus a CV-optimisation training.

Project2017 - 19

Internal projects I led as project / technical lead

Togethair2018 - 19

Project lead / manager - junior training project

A generic internal project handed to young starters to test and grow their skills. Sourced and coached the product owner, framed the goal, scope and approach, and set up a feedback culture so the teams could adjust fast.

JavaJPAJSFJEEGitScrumbanAgile
  • Sourced and coached the product owner; explained needs, goal and approach
  • Set scope and found experienced developers to support the starters
  • Split starters into teams by competency and built the planning
  • Set up a feedback culture to react and steer quickly
  • Attended demos and gave feedback
R-ESCue2018 - 19

Project lead, technical lead & scrum master

Led a confidential internal project as the bridge between the functional and technical sides. Set up the project and architecture, coached analysts and developers, and ran the facilitation meetings.

SpringAngularIonicCordovaJavaMySQLGitLabAzureTFS
  • Set up project and architecture; chose the methodology
  • Coached analysts (functional) and developers (technical)
  • Ran code reviews and set conventions: code style, naming, version control
  • Bridged the functional and technical sides
  • Defined sprints and deadlines; ran stand-ups, retros and demos
  • Set team and task allocation
Sportclub2017 - 18

Project lead & technical lead

A SaaS solution for different kinds of sports clubs, with a generic core and a sport-specific layer. Same lead role as R-ESCue: set up the project and architecture, coached the team, and ran the ceremonies.

SpringAngularJavaPostgreSQLGitLabHerokuTFS
  • Set up project and architecture; chose the methodology
  • Coached analysts and developers; ran code reviews and conventions
  • Bridged the functional and technical sides
  • Defined sprints and deadlines; ran stand-ups, retros and demos
YPTO / NMBS2021 - 22

Technical lead - backup scrum master

Rebuilt the ticketing APIs (TFC) behind the Digital Train Assistant device for train conductors, plus digital subscription and voucher purchasing (AboOnWeb). Drove the migration to a new Kubernetes platform and introduced best practices across teams.

Spring BootKubernetesDockerTomcatOraclePostgreSQLHibernateActiveMQJMSFlywaySwaggerSonarQubeJenkinsKibanaJWTAxway gatewayBitbucket
  • Went the extra mile to hit a near-impossible deadline
  • Introduced cross-team best practices (DevOps, Spring, Git); coached consultants
  • Helped shape architecture and solutions to problems
  • Backup scrum master for the team
Universiteit Gent2020 - 21

Lead developer - senior Spring developer

Rewrote legacy JEE/JSF and PHP applications (visitor cards, room requests, personal-data handling) to Spring, end to end: analysis, development, testing, go-live and data migration.

SpringThymeleafPostgreSQLH2LiquibaseHibernateMapStructLombokSpring SecurityTomcatJenkinsBambooLDAPArtifactory
  • Owned two application rewrites (Bezoekerskaart, Kameraanvraag) from A to Z
  • Wore multiple hats: analyst, developer, tester, project lead
  • Retrained a Pascal developer to Java/Spring
  • Ran go-live plans and data migration across tst / qas / prd
  • Helped maintain and extend UGent's shared Spring libraries
Smals2018 - 20

Senior fullstack - buildmaster / architect - SPOC

Built the platform financing Flemish residential-care centres and mobility aids under the Flemish Social Protection reform, split into tribes by functionality. Owned buildmaster and architect duties across a microservices estate, and acted as SPOC and backup team lead for 20+ consultants.

Spring BootSpring BatchMicroservicesKubernetesDockerRed Hat OpenShiftAngularTypeScriptPostgreSQLGradleGitLabJenkinsRabbitMQSeleniumCQRSDDDHATEOASSwagger
  • Buildmaster / architect: applied architecture choices across all microservices
  • Coordinated releases and deploys across dev / test / acc / int / prod
  • Monitored SonarQube quality gates and Jenkins builds, fixing what broke
  • Defined test types (unit, service, integration, e2e/Selenium) and ran a Pact PoC
  • Wrote technical and functional documentation; investigated acc/prod issues
  • Ran performance tests and organised knowledge-sharing sessions
  • SPOC and backup team lead for 20+ Inetum-Realdolmen consultants at Smals
  • Chief coordinator for client demos
FOD Economie · EuCertificates2017 - 18

SOA developer

A public and internal web application for people established in Belgium who want to run their activity in another EU country. Finished the incomplete functional analysis myself by talking to the business and translating needs into use cases, then built both apps front to back.

JavaJEE 7JPAJSFPrimeFacesJAX-WSJAXBSOADB2EclipseLinkFlywayMockitoDbUnitJRebelMavenGitJira
  • Finished the functional analysis and translated business needs into use cases
  • Estimated and prioritised issues; planned the facilitation meetings
  • Built the public and internal web apps, front and back end
  • Set the application architecture, builders and facade, and best practices
  • Co-built a generic base project to reuse across future projects
  • Integrated external web services / security: KBO, KSZ, RRN/BIS, CSAM
FOD Economie · Index2017

Lead Android developer

An Android tablet app for the monthly consumer-price index, replacing a pen-and-paper process where agents wrote prices on their rounds and typed them in later. Owned the architecture, GUI and UX, and led the development team.

JavaAndroid SDKAndroid StudioMySQLJSONButterKnifeDBFlowProGuardMultidexSVNMaven
  • Point of contact for everything Android; set the code conventions
  • Owned architecture, GUI and UX of the app
  • Used an injection framework and MVC / observer / adapter / view-holder patterns
  • Ran demos for the business and gathered improvements
  • Dutch-language support in meetings for a French-speaking team and user base
FOD Justitie2016 - 17

Software developer - Central Criminal Register

Worked on the Central Criminal Register: web apps for internal justice users and magistrates, an app for municipalities, and two web services. Beyond feature work I rebuilt the entire build and deployment process and did deep Oracle SQL tuning.

Spring 3Spring BatchAngularJSJSFSOAPOracle SQLAjaxMavenNexusJenkinsGitSoapUI
  • Rewrote the whole build/deployment process; reworked 200+ Maven dependencies
  • Set up a Nexus repository manager and fixed dependency management
  • Oracle SQL tuning: cut a 2+ day script down to 2 hours
  • Fully documented an undocumented part of the app and improved the process
  • Corrected corrupt production data; defined and ran performance tests
  • Build master and Git master: guarding guidelines and fixing broken builds
  • Onboarded and supported two colleagues; ran client demos
MediHoo2015 - 16

Developer, analyst & UX/UI designer

Sole owner of a hybrid iOS/Android app supporting a healthcare community: search providers (hospitals, dentists, home care...) by classification and location, rate and favourite them, in five languages. Ran the PoC, wireframes, development and store release.

IonicAngularJSCordovaJavaScriptHTML5CSS3GulpElasticsearchAzureGitGitHub
  • Full responsibility for the project, A to Z
  • PoC to pick the stack (native vs hybrid; React Native, Cordova, Xamarin...)
  • Analysis and wireframes; regular client sync to steer development
  • Built the Ionic hybrid app on an existing Elasticsearch backend on Azure
  • Five-language support in frontend and API
  • Supported the client through App Store and Play Store release
Xploregroup2015

Full-stack JS developer & project lead - internship

Internship project "Plek": a hybrid iOS/Android app that lets a group check and share whether there is space somewhere, using Twitter login and websockets. Did the analysis, development, CI/CD and led the small team.

AngularJSIonicNode.jsCordovaPhoneGapWebSocketsJWTRESTKarmaJasmineProtractorGulpGitGitHub
  • Analysis: domain model, use cases, sequence diagrams, wireframes
  • Built features: Twitter login, websockets, security, mobile multitasking
  • Set up continuous integration for automatic deployments
  • Owned database consistency and wrote documentation / user manuals
  • Led the team as project lead: admin, work allocation, reviewing delivered work
Courses & certifications
Technical & conferences
AI Coder: Vibe Coder to Agentic EngineerEd Donner / Udemy - 2026
SAFe 4.0 Scrum Master (SSM)certification - 2017
Angular 2 Master ClassThoughtram - 2016
Gang of Four Design Patterns2017
Java acADDemICT trackInetum-Realdolmen - 2015
Spring I/O Barcelona2019 - 26
Devoxx Belgium2016 - 23
SpringOne2020 - 23
SpringOne Tour Toronto2019
AxonIQ Conference2022
Jakarta One2019
NG-BE Angular Belgium2017
Coaching & leadership
Leadership Excellence Program (LEP): conflict management, giving & receiving feedback, personal productivity, mental resilience, stress management, self-awareness, handling psychosocial issues2021 - 22
Coaching & leading teams (modules 1 & 2, handling conflict)Cevora - 2017 - 19
Recognising & managing stress and burnout for leadsIdewe - 2019 - 20
Managing stress and negative emotionsCevora - 2020 - 22
Managing remotelyCevora - 2021
Project management basicsCevora - 2017
Foursights thinking profile2021
Insights (team dynamics)2017 - 18
Writing
Radar

Notes from the frontier of AI-assisted development - what I actually tried, what actually broke, what I would do again. Weekly finds, monthly deep dives with real numbers.

Read Radar
Contact

Available for freelance backend, platform, and coaching work - and conversations about doing AI-assisted engineering properly.