Custom websites & business software

No-nonsense, ready for tens of thousands (or millions) of users

I design and build robust software systems — primarily with Django on Ubuntu/Debian — for companies that value long-term quality over short-term cost.

Over the years, the platforms and backend systems I’ve delivered have generated significant measurable value for my clients. I work with a small number of organisations that take their technical foundations seriously and are prepared to invest accordingly.

I specialise in:

  • Django-based platforms and complex backend systems
  • Ubuntu/Debian server architecture and deployment
  • User interface design
  • Custom software, APIs and integrations
  • Front-end JavaScript & CSS
  • PHP when the project requires it
  • Reliable, maintainable code that lasts

I live and work in Haarlem. You can call me or reach me via WhatsApp at +31(0)23 234 0012.

Yessica van Roozendaal - senior webdeveloper
Yessica van Roozendaal
High-quality

Full service 

  • Strategy
  • Design
  • Code
  • Cloud Hosting
Ferskaat MP – Christina van der Bijl

Custom e-commerce website  
(English below) “Het is een genoegen om met Yessica van Tektonikos samen te werken, want ze heeft zich bewezen als iemand die prettig in de omgang is en duidelijk communiceert. “

“It is a pleasure to work with Yessica from Tektonikos, as she has proven herself to be someone who is pleasant to work with and communicates clearly.“

BabyBalance BV – Monique van der Slaa & Grietje Miedema 

E-health Femtech platform  

(English below) “Juist het meedenken van Tektonikos waarderen wij zeer, zoals aanpassingen uit eigen initiatief. “

“We particularly appreciate Tektonikos’s proactive approach, such as adjustments made on their own initiative. “

Cervino Data BV – Jacco Drenth & Erik van Dorp 

Development big data marketing-programmatuur  
(English below)“We zijn blij dat Tektonikos op ons pad is gekomen, want het waren geen gemakkelijke opdrachten. “

“We are happy that Tektonikos crossed our path, because they were not easy assignments.”

Can you also..?

If you are wondering whether I am familiar with a specific working method or technology, take a look at this list. Is what you are looking for not listed? I might know it after all, or I can learn it right away, so feel free to ask.

Strategy: product statement, empathy map, funnel optimization, scrum, waterfall project management, A/B testing, SEO, speed optimization
Front-end: CSS, Sass, JavaScript, Reactjs, Vanilla JS, barrier-free, bootstrap
Back-end: Python, Django, PHP, Laravel, Symfony, WordPress, Node.js, Postgres, MySQL, database normalization, Git
API integrations: oAuth2, Saml2, mollie, stripe, contentful, directus, postmark, laposta, mailchimp and dozens more. AI: faster coding using AI, custom chatbots that comply with European guidelines, image generation
Hosting: Debian, Ubuntu, RedHat, Digital Ocean, Amazon Web Services (AWS), Google Cloud, Docker

Ready to grow your idea – whether it is a startup, a business platform, or a large-scale service?

Get in touch and we will discuss how we can build a scalable, secure, and user-friendly solution together.