Alexander Esselink

Fullstack web developer · Delft, Netherlands +31 6 2303 4351 · dexter@dexterlabs.nl

github.com/dxlbnl · linkedin · dexterlabs.nl

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Summary

Fullstack developer, 13+ years in. TypeScript and React in production most of the time; broader fullstack work on my own projects (real-time sync, offline-first apps, WebRTC, hardware). I like owning a feature end-to-end, from schema through to deployment. I tend to be the person pushing for new tools and the one teammates come to with hard questions. Outside of work I run Dexterlabs, a small hardware and software lab in Delft.

Selected stack: TypeScript · React · Svelte/SvelteKit · Node · GraphQL · Postgres · Docker · Kubernetes

Skills

Languages TypeScript JavaScript (ES6+) Python Rust C++

Frontend React Svelte/SvelteKit Chakra-UI CSS Storybook

Backend Node.js GraphQL Postgres Python

Infra Docker Kubernetes Nginx GitLab CI GitHub Actions Linux GCP AWS

Other WebRTC WebSockets ESP32 firmware

Spoken Dutch English

Experience

FIOD — TypeScript Developer 2021–PRESENT

via Passionate People 2021–2025, direct 2025–Present

• Build and own data analysis tools for investigators, running as part of a microservices stack.
• Brought TypeScript, Chakra-UI, and a type-safe Zod API layer into the codebase.
• Set up the design system and wired it into Storybook.
• Built and maintain the GitLab CI pipelines, including containerized deploys to Kubernetes.
• Help design backend services and own the troubleshooting when API or data integration bugs get tricky.
• Go-to person on the team for code review, UX feasibility questions, and tricky technical calls.
• Stack: React TypeScript Chakra-UI Zod Node.js Docker Kubernetes GitLab CI

Passionate People — TypeScript Developer Consultant 2019–2025

• Consultant role, placed primarily at FIOD and ING (see entries below).
• Across engagements: API design with backend teams, helping clients adopt containerization and CI/CD, mentoring teammates, and pushing on architecture decisions.

ING — JavaScript Developer 2019–2021

via Passionate People

• Built a component-based mortgage calculator used across several of ING’s client funnels.
• Set up CI/CD so each funnel could ship updates independently.
• Stack: LIT JavaScript CSS Node.js

Kabelfabriek, Delft — Web Developer 2011–2022

(part-time side role)

• Built full-stack websites and systems for a range of clients.
• Stack: TypeScript JavaScript React Svelte CSS PHP WordPress MySQL Python

Nerdalize, Delft — Web Developer 2017–2018

• Built a frontend dashboard and integrated backend services for a cloud-computing startup.
• Stack: JavaScript Django PostgreSQL

Freelance — Fullstack Engineer 2014–2018

• Velotype: Android app with USB integration.
• MyAethon: Online resource-management platform on Django + Angular.
• GingerPayments: PSP dashboard on Angular + AWS.
• Megurumi: Web app for generating crochet doll patterns with PDF rendering.

Earlier roles 2012–2014

• Hansje Brinker, Delft — Software engineer. Online GIS for visualizing elevation deformation maps, with backend API. (JavaScript, Python)
• Fenestrae, Den Haag — Software engineer. JavaScript application for scanning, emailing, and faxing documents from a multifunction printer, with backend integration. (Python, JavaScript)

Projects

Dexterlabs — Independent hardware & software lab 2019–Present

dexterlabs.nl

Solo operation designing, building, and shipping Eurorack hardware and software end-to-end: concept, electronics, firmware, and web.

zod4-mock TypeScript · Zod

writeup

TypeScript library that generates mock data from Zod v4 schemas. Same seed gives byte-identical output, and relational identity is preserved across schemas. There’s a live playground.

Lists SvelteKit · TypeScript · offline-first

writeup

Real-time shared lists with passwordless auth and offline-first sync. Rebuilt v2 around an offline-first architecture so it stays useful with flaky or no connection.

Private Share WebRTC · SvelteKit · TypeScript

writeup

Peer-to-peer sharing of text and files across devices. Nothing touches the server.

Members Svelte · Drizze · Postgres · Nginx

Authentication, access control, and member management for an association. SSO across multiple services via Nginx sub-requests.

Speaking

Building Distrans AR-1 with AI 0xFEFE · Apr 2026

Svelte: The Last Framework We Need? Frontend Developer Love

Continuous Learning

Started in Electrical Engineering at TU Delft and The Hague University of Applied Sciences. Software pulled harder, and I’ve been self-taught ever since, picking up languages, frameworks, and entire stacks by building things with them. Recent additions include Rust (Bifrost lighting control), SvelteKit with offline-first sync (Lists), Zod-based tooling (zod4-mock), and ESP32 firmware for hardware I now design and sell through Dexterlabs.