About me
One developer you can reach
I am Patrick Willemsen, a full-stack software engineer from ’s-Hertogenbosch and the owner of BugFyx.

- 8+ years of experience
- BSc ICT & Software Engineering, Fontys University of Applied Sciences, Eindhoven (2021)
- Based in ’s-Hertogenbosch
- Insured for professional liability
I have been building software that a lot depends on for 8+ years. At ING I worked on InsideBusiness, the platform multinationals and governments bank with, and helped recover the application after incidents. At ABN AMRO and de Volksbank I built applications and integrations that simply have to work, and at VodafoneZiggo I kept a system with more than 80 web shops running.
At TCS, as lead AI integration engineer, I built an app with large language models from start to finish. There I saw how fast you can build something with AI, and how much more it takes afterwards to make it secure and reliable.
That is what I do with BugFyx. Founders and companies build with AI faster than ever, and I make sure their app stays secure, stable and online. I also build custom software, such as my own SaaS Traecy.
Where I have worked
ABN AMRO 2026 – now
Java software engineer
New applications through the whole development cycle: designing and building APIs, writing tests, deploying through CI/CD and monitoring in production.
TCS 2025 – 2026
Lead AI integration engineer and Java software engineer
Built an app with large language models end to end, and turned an outdated system that processes more than 100,000 invoices a year into tested Java services.
ING 2022 · 2024 – 2025
Java software engineer
Features and bug fixes for InsideBusiness, ING’s wholesale banking platform, helped recover the application after incidents, and built ESG reports for regulators.
Benerail 2023 – 2024
Lead Java software engineer and scrum master
An API following the OSDM standard that lets travel agents worldwide book European rail travel, in a team of two.
VodafoneZiggo 2021 – 2022
Full-stack software engineer, through FrontWave
Maintenance and new features for a CMS running more than 80 web shops, where downtime during peak traffic is not an option.
de Volksbank 2020 – 2021
Java integration specialist
Spring Boot integrations between the bank’s COBOL systems and the software of mortgage advisers, including CI/CD and coaching a junior developer.
How I work
Reachable
You email me, and depending on your plan you message or call me. No ticket system and no rotating developers.
Honest
I say what I do and don’t do. Fixed prices, response times in writing and no promises I can’t keep.
Precise
I look for the cause of a bug instead of the symptom, and test that the rest keeps working.
No jargon
You don’t need to be a developer to understand what is going on with your app.
Company details
- Company name
- BugFyx B.V.
- Address
- Siloweg 3, 5222 BN ’s-Hertogenbosch
- Chamber of Commerce (KvK) number
- 85781517
- VAT number
- NL863739842B01
Know where your app stands within 5 working days
With the App Check you get a clear report on security, database, hosting and backups for €600. If you take a maintenance plan afterwards, I credit the €600 in full.
- Fixed price
- Plain-language report
- Within 5 working days