Daniëlvan 't OeverFreelance engineer
Java and Kotlin specialist: solid backends, plus apps for the TV, the phone and the web.
Worked forINGDUOEDSNTKPCJIB
Northern Netherlands · remote or on site
About
Fifteen years of backends. Now I build the whole thing.
I'm Daniël, a software engineer from Een, just outside Roden in Drenthe. I studied computer science at Saxion and the University of Twente, started as a functional designer at KPN, and then spent eleven years with Quintor on assignments at ING, DUO and CJIB. Since 2023 I work for myself as VTO Software Development.
My clients are banks, pension funds and government: payments, pensions, exam infrastructure and energy data. Colleagues describe me as the developer who explains technical choices clearly to non-technical people, and who helps the rest of the team get better along the way.
I work 32 hours a week for clients. The fifth day goes to products of my own and for people around me: apps for Apple TV and Android TV, iPhone apps, and websites for local businesses and clubs. AI tools changed how fast one person can ship. I use them every day, with the habits of someone who has kept large systems running.
Now:Freelance at DUO. Always open to a conversation about what comes next.
- years building software
- 15+
- projects on this page
- 10
- platforms, TV to web
- 8
Backend
Apple
Apps & web
Delivery
What I do
What you can hire me for
Backend development
Java, Kotlin, Spring Boot and SQL. Robust services and APIs. The backend is home, but you can count on me for the frontend too.
Quality
Unit, integration and, where it matters, load tests. They run automatically in the pipeline after every change, before anything reaches a test environment.
Cloud
AWS Certified Developer. Docker, stateless APIs, Kafka and Spring Cloud for applications that have to scale.
Team lead
If you want it: making the right choices together, reviewing with care, and making sure everyone contributes something useful.
Apps & websites
Native apps for iPhone, Apple TV, Android TV and the Mac, and fast websites. From the first idea to the store listing.
AI-assisted development
Tools like Claude Code, combined with the engineering habits that keep production calm. Faster, without cutting corners.
Worked for
- ING
- DUO
- EDSN
- TKP
- CJIB
- KPN
Selected work
Projects
- Prototype €799Your project?A working prototype within two weeks.
- NasCamSynology cameras on Apple TV & Android TV
- ServicePortalOffline field-service forms for Service Groep
- Bier-RadarThe cheapest beer deal around the corner
- BikeLockNo videos while your kid is cycling
- HandRestCatch the face-touching habit at your desk
- Capel & CapelFine art dealers since 1902
- Flying RedA new website for the basketball club in Roden
- Ping TVA real ping utility for Apple TV
- Beetstra TrainingAn iPhone app and website for a personal trainer
- 3D for VitureStereo 3D models on XR glasses
Resume
Where I've been
Fifteen years of Java at banks, pension funds and government. Freelance since 2023.Lead dev
- 2025 – now
Read more about DUOModernising the Modelling service team
Software implementation specialistModernising the tooling of 300 information analysts: from Velocity-based Word templates to a web portal, with event-driven webhooks and a more mature CI/CD setup. - 2024 – 2025
Read more about EDSNDailySync 2
Senior developerBuilt the sync layer that let a legacy energy-data monolith be replaced by Kafka-based microservices, with output checked daily against production for 7 energy companies. - 2023 – 2024
Read more about TKPChamber of Commerce API
Lead developerLead developer on the contract administration behind TKP’s risk-based pensions. Coached colleagues and built a new REST service for Chamber of Commerce updates. - 20223 recommendations
Read more about INGiDEAL 2.0 & Belgian transactions API
Lead / senior developerBuilt features for the new iDEAL 2.0 payment platform, and was technical lead for an API that shows transactions to ING customers in Belgium. - 2020 – 20222 recommendations
Read more about CJIBAttachment of accounts and income
Full-stack developerAngular and Java for a collection app that keeps fines from being passed on to bailiffs, and the extra costs that come with that. - 2015 – 20201 recommendation
Read more about DUOFacet
Java software architectRebuilt the online exam platform with stateless, scalable APIs, so 30,000 students can sit an exam at the same time. - 2013 – 2015
Read more about INGGenerated web forms
Java developerHighly available APIs that send customer confirmations by email with PDF attachments, and a Groovy DSL that generates multichannel forms. - 2012 – 2013
Read more about CJIBE-register
Java developerSet up the e-register for looking up traffic fines, and a link with the Public Prosecution Service. - 2011 – 2012
Read more about QuintorOnlineveilingmeester.nl
Java developerA full rebuild of an online auction site, so it stays fast when an auction gets busy. - 2008 – 2011
Read more about KPNSiebel CRM for fibre
Functional designerFunctional designer for the customer systems behind KPN’s ADSL and fibre. Five releases into production.
Start a new project
Let's work
together!
Freelance work, a second opinion on an architecture, or an app idea you want to see running on a real device. I'd like to hear about it.