I am Lasse

About me

Full-stack tech lead and developer with 15+ years of experience planning, architecting, and building web and mobile products. I have spent most of my career inside international startups and scale-ups in Berlin and Copenhagen — leading teams, owning architecture decisions, and helping early-stage companies grow into successful businesses.

I have worked with AI since OpenAI released GPT-3 and have built and launched four AI products of my own, including the profitable SQLAI.ai. That work spans the practical side of applied AI — RAG, embeddings and vector search, prompt design, and AI-assisted development — always aimed at solving real business problems rather than producing demos.

Beyond the code, I bring the business judgment that comes from startup environments: strong product thinking, a good eye for UX/UI, and code that stays simple, testable, and maintainable. When leading teams, I value results over processes and personal responsibility over micro-management.

Read a few of my thoughts on what's important for ensuring good architecture.

I speak Danish, German and English.

📍Based in Copenhagen.

AI products

Products I designed, built, and run end to end — from idea and architecture to UX, marketing, and revenue.

SQLAI.ai

AI-powered SQL workspace for generating, explaining, and optimizing SQL without losing control.

Since 2023 · Profitable

Chartmaker.io

Turns rough input and raw data into clean, presentation-ready charts with minimal setup.

Since 2024

WebsiteFeedback.ai

AI feedback on landing pages and marketing sites: clarity, positioning, UX, and first impressions.

Since 2024

ViewDiff.ai

AI-assisted diff viewer for professional writers, editors, and editorial workflows.

Since 2025

Selected client work

Roles I have held for startups and public institutions:

• Architected and developed the native mobile and web apps for a delivery service, with end-to-end responsibility for design, structure, and technical implementation, while mentoring teammates.
  Customer: alpakas.app · alpakas.app
  Tech: React Native, React, TypeScript, GraphQL.
  Date: Jan 2022.
• Developed the native mobile app for a Berlin crypto bank, focused on secure and user-friendly access to digital banking services.
  Customer: nuri.com · nuri.com
  Tech: React Native, TypeScript, GraphQL.
  Date: Feb 2021 - Sep 2021.
• Developer and tech lead on Germany's first complete platform for end-to-end digital car purchases. Designed and implemented the fully digital customer journey — selection, configuration, purchase, and transaction flows — and shaped the product through user interviews, analytics, feature flags, and A/B testing.
  Customer: hey.car · hey.car
  Tech: SSR React, Redux, CSS-in-JS, Kotlin REST API.
  Date: Aug 2018 - Nov 2020.
• Developed a React application for a Berlin e-learning startup using test-driven development, working both independently and as part of the team.
  Customer: Wonderwerk.co · wonderwerk.co
  Tech: React, JavaScript, TDD.
  Date: Aug 2018 - Dec 2018.
• Long-term freelance developer through the Copenhagen agency Headnet, delivering full-stack projects for public institutions and startups:
  • Danish Ministry of Higher Education and Science: embeddable webshop with an order/product backend and advanced data export (React, Redux, Flask, MySQL).
  • The National Museum of Denmark: portal for exploring the museum's digitized collection with rich search (natmus.dk; Angular, Express, Elasticsearch).
  • Danish Environmental Board of Appeal: map of protected buildings in Denmark built on geospatial queries (fredninger.dk; Backbone, Flask, Elasticsearch, Docker).
  • The Foundation for Environmental Education: CartoDB–Podio integration visualizing geodata across map views (Laravel, MySQL).
  • Bolighed: map-based frontend features for housing search for a Danish startup (Angular, geodata).
  Date: Jun 2013 - Jan 2018.

Technologies

I work across the modern TypeScript stack, with React at the center — from frontend architecture and APIs to data modeling, testing, and delivery. AI is a first-class part of my toolbox, both in the products I build and in how I build them. The lists below are representative rather than exhaustive.

Open source

Selected open source projects I developed and maintain:

• Popular package for ES7, React, Redux and React​Native snippets for Sublime Editor (JS & TS).
• flask-reactjs: Flask, React/Redux and webpack boilerplate.
• flask-scaffolding: Flask scaffolding featuring SQLAlchemy, BackboneJS and Sass.
• react-collapse-simple: Simple library for collapsing and expanding content with sliding animation (TypeScript).
• react-simple-social: Add all social share links through one simple and lightweight React component.
• git18n-node: Lightweight npm package that abstracts translation management for developers.
• Browser extensions for quick dictionary and translation lookups: DeepL, Langenscheidt and Ordnet.

See more on my GitHub profile →