About me.

Full-stack engineer with a mathematics background, specializing in web accessibility (EN 301 549). Based in Germany and the Netherlands.

Portrait of Daniel Kosbab

How I think about software

I'm 29, a full-stack engineer with a mathematics degree, working between Germany and the Netherlands. Math taught me to see patterns, think in systems, and break complex problems into clean, logical steps. That's still how I approach every line of code.

I also specialize in web accessibility (EN 301 549). My brain latches onto edge cases: I see the ways things break before I see the happy path. If a site doesn't work with a screen reader, it's broken. Period. I dive deep into these problems until they're actually solved, not just "fixed." Half-complete solutions bother me in a way that's hard to explain.

What I work on.

  • Mathematics

    Strong foundation in mathematical modeling, optimization algorithms, and statistical analysis. Applying theoretical concepts to solve real-world challenges.

    Focus
    Modeling & optimization
    Applied to
    ML, data science

  • Full-Stack Engineering

    End-to-end application engineering from database design to responsive frontends. Modern tech stack with React, Next.js, TypeScript, Node.js, and PostgreSQL.

    Stack
    React, Next, Node
    Focus
    TypeScript, SQL

  • Web Accessibility

    Expert in EN 301 549 standard. Building inclusive digital experiences that work for everyone, including assistive technology users.

    Standard
    EN 301 549
    Target
    WCAG 2.2 AA

Projects.

  • DeepSpectrum Lab

    Period: 2024 – Present

    A community of neurodivergent developers (autism, ADHD) building software that helps neurodivergent children train socio-emotional skills.

    • Machine Learning
    • React
    • Next.js
    • Python
    • Accessibility

  • Mathematics Teacher (Pro Bono)

    Period: 2025 – Present

    Voluntary mathematics teaching at VU Amsterdam. Helping students build intuition for abstract concepts and bridge the gap between theory and application.

    • Mathematics
    • Teaching
    • University
    • Pro Bono

  • Elevenly (A11Y for Shops and Web Apps)

    Period: 2025 – Present

    Accessibility testing for online shops and web apps. Elevenly scans the pages and walks a shop's user flows up to checkout like someone who only uses the keyboard and a screen reader, without ever placing an order. Every barrier is explained in plain language, with who it affects and how to fix it. My part: product and engineering.

    • Accessibility
    • Machine Learning
    • Next.js
    • Playwright
    • axe-core
    • WCAG 2.2

  • FrOSCon Volunteer & Speaker

    Period: 2019 – 2024

    Volunteer and speaker at the Free and Open Source Software Conference (FrOSCon) at Hochschule Bonn-Rhein-Sieg, one of Germany's largest open-source community events.

    • Open Source
    • Community
    • Conference
    • Speaking

  • Programming Tutor

    Period: 2019 – 2021

    Tutoring computer science students at Hochschule Bonn-Rhein-Sieg. Covering programming fundamentals, data structures, and algorithms.

    • Teaching
    • Computer Science
    • University
    • Java

Tools.

ML & Data Science

  • Python
  • R
  • PyTorch
  • TensorFlow
  • scikit-learn
  • Keras
  • OpenCV
  • Pandas
  • NumPy
  • Plotly
  • Jupyter

Frontend

  • React
  • Next.js
  • Gatsby
  • TypeScript
  • JavaScript
  • Tailwind CSS

Backend & Infra

  • Node.js
  • FastAPI
  • GraphQL
  • Docker
  • Kubernetes

Databases

  • PostgreSQL
  • MySQL
  • MongoDB
  • Supabase
  • Firebase

Tools & Workflow

  • Git
  • GitHub
  • Storybook