Nils Siemsen

I am a fullstack developer with over six years of experience in web development, specializing in frontend and backend technologies. My focus is on scalable, user-centered applications that solve real business cases.

I have worked as a freelancer, lecturer, and developer in startups, agencies, and corporations, and thanks to my strong communication skills, leadership experience, and didactic background, I am happy to take on technical responsibility in interdisciplinary teams.

Let's get together 🚀

Technologies

Vue.js

React.js

Angular

Node.js

Express.js

Nest.js

JavaScript

TypeScript

PHP

Laravel

Kotlin

Java

Quarkus

MongoDB

SQL

CSS

SASS

Tailwind

Docker

Kubernetes

Career

2025 – today
Senior Fullstack Developer
Online Akademie GmbH
- HTML
- CSS
- TailwindCSS
- JavaScript
- TypeScript
- Node.js
- Vue.js
- PHP
- Laravel
- SQL
- Docker
Fullstack development of a comparison platform for the education sector with marketing features, an administration interface, and a customer portal.
2025
Freelance Software Developer
Self-employed
- HTML
- CSS
- TailwindCSS
- SCSS
- JavaScript
- TypeScript
- Node.js
- Vue.js
- Kotlin
- Java
- Quarkus
- SQL
- Docker
- Kubernetes
Requirements analysis, conceptualization, and development of fullstack applications in a startup environment as part of self-employed work.
2024 – 2025
Fullstack Developer
right. based on science GmbH
- HTML
- CSS
- TailwindCSS
- SCSS
- JavaScript
- TypeScript
- Node.js
- Vue.js
- Kotlin
- Java
- Quarkus
- SQL
- Docker
- Kubernetes
Conceptualization and development of tools for managing corporate climate impact for large enterprises in the banking, industrial, and real estate sectors.
2024
Lecturer
Neu-Ulm University of Applied Sciences
- HTML
- CSS
- JavaScript
- Node.js
- Express.js
- SQL
Leading a university seminar on teaching the fundamentals of web engineering in person: supervising and evaluating a fullstack application as a project-based examination.
2021 – 2024
Fullstack Developer, Project Manager
Lemonize
- HTML
- CSS
- TailwindCSS
- SCSS
- JavaScript
- TypeScript
- Node.js
- Vue.js
- Angular
- Java
- Magnolia CMS
- PHP
- Laravel
- Statamic CMS
- SQL
- Docker
- Kubernetes
Project management as well as conceptualization and development of marketing solutions and web applications for companies across various industries, and acting as lead developer in multiple projects.
2020 – 2021
Bachelor’s Thesis Student
Lemonize
- HTML
- CSS
- SCSS
- JavaScript
- TypeScript
- Vue.js
- Node.js
- Express.js
- MongoDB
Writing a bachelor’s thesis on the topic of Software-as-a-Service, accompanied by the implementation of a SaaS solution for a digital agency.
2019 – 2020
Tutor
Neu-Ulm University of Applied Sciences
- HTML
- CSS
- JavaScript
- Node.js
- Express.js
- SQL
Conducting tutorial sessions to support students in the subject of web engineering and mentoring project work.
2019
Internship
Daimler TSS
- HTML
- CSS
- JavaScript
- TypeScript
- Node.js
- Express.js
- Java
- Spring
- SQL
Practical semester in web development for an internal corporate portal.