Simon Kemmerling - Senior Fullstack Developer, Frontend

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Available

Overath, Germany

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Experience

Jan 2025 - Present

1 year 9 months

Fullstack Developer

RTL Technology GmbH

Development of a browser-based video logger for the automated enrichment of metadata to optimize video search and categorization in the company’s editorial tool. The platform enables editors to efficiently analyze video content and add additional information.
AI-supported scene recognition for the automatic generation of video shots and time markers
Automatic transcription and speech analysis for extracting relevant content
Enhanced metadata management to improve search and archiving functions
Event-driven architecture in the frontend (Angular, TypeScript)
Backend integration (.NET) with video streaming and data processing

Nov 2024 - Present

1 year 11 months

Solution Architect

CPlus - Vetworking, No-Code/Low-Code

Development of a No-Code/Low-Code web platform with Bubble.io for booking and managing online webinars. The solution enables users to select and book webinars through an integrated shop, while all processes—from payment to participant communication—were automated.
No-Code shop with Bubble.io for easy booking and management of webinars
Automated payment processing via Mollie
Invoicing and financial integration with FastBill
Workflow automation through Zapier for invitations, reminders, and confirmations
Help system with Helpsout to support users

Oct 2022 - Dec 2024

2 years 3 months

Fullstack Developer

RTL Technology GmbH

Development of a browser-based video editor for cutting and adding sound to videos, based on a specially developed streaming process using the MediaSource API.
Integration into the company’s editorial tool, allowing editors to research and edit videos and make them available for backend processing.
Architecture and implementation of an event-driven frontend application based on Angular.
Development of a TypeScript-based application service for efficient communication between web components.
.NET backend applications for implementing video and audio streaming functionality.

Apr 2022 - Aug 2022

5 months

Performance Analyst, Frontend Developer

Fressnapf Tiernahrungs GmbH

Performance analysis for Fressnapf’s multilingual shop and definition of measures to improve the PageSpeed score. The scores improved by 70% after implementing the recommendations: mobile from 30 to 50 points and desktop from 70 to 90.
Implemented more complex measures and optimizations for the Nuxt.js application.

Apr 2022 - Aug 2022

5 months

Lead Fullstack Developer

KMH GmbH

Rebuilt a telesales service for creating online quotes for a large energy company. Implemented all backend functionality as Lead Developer and defined the frontend architecture.
Backend: implemented AWS Lambda, TypeScript, Yup, node.js, and a REST API with Serverless; created API documentation with OpenAPI; MJML for responsive email templates
Frontend: Vue3, Tailwind.css
Mentor for junior developers

Jan 2022 - Present

4 years 9 months

Freelance Full Stack Developer

Self-employed / Freelance

Jan 2022 - Apr 2022

4 months

Fullstack Developer

KMH GmbH

Full Stack development of an application for interior landscapers based on Vue and Node.js. Communication between the frontend and backend runs through a GraphQL API. The PostgreSQL database is accessed via TypeORM (entities, query builder).
Backend: Node.js, GraphQL, TypeORM, PostgreSQL, TypeScript, AWS Lambda, Serverless
Frontend: Vue.js, TypeScript,
Other: Stripe setup and integration (frontend and backend)

Jan 2019 - Dec 2021

3 years

Director Frontend & IT, Member of the Board

brandung GmbH & Co. KG

Feb 2018 - Dec 2018

11 months

On-site

Senior Frontend Developer

1. FC Köln 24/7

SPA (Single Page Application) with Angular for a paid video content portal
Spryker Cloud Commerce as the backend solution and SAML SSO flow via Salesforce

May 2016 - Dec 2018

2 years 8 months

Director Frontend & Operations, Member of the Board

brandung GmbH & Co. KG

Jun 2013 - Apr 2016

2 years 11 months

Head of Frontend

brandung GmbH & Co. KG

Jan 2010 - May 2013

3 years 5 months

Senior Frontend Developer

brandung GmbH & Co. KG

Jan 2005 - Dec 2009

5 years

Art Director Online, Frontend Developer

brandung GmbH

May 2002 - Dec 2003

1 year 8 months

Founder, Entrepreneur

tools & tales Gbr

Jan 2000 - Dec 2004

5 years

Freelance Frontend Developer

Self-employed / Freelance

Jan 1998 - Apr 2002

4 years 4 months

Junior AD & Web Developer

DISENO

Frontend Consultant | Lead Frontend Developer

C&A

Responsive frontend implementation of the C&A shop based on modular, responsive components in HTML, CSS/SASS, and JavaScript
Template engine with Handlebars and automatic generation of an online style guide with Storybook
Automated deployment pipeline
IBM WebSphere e-commerce shop system with 26 country shops
Page speed optimization with automatic measurement in the CI/CD pipeline and monitoring via Grafana and Sidespeed.io
Agile way of working in an interdisciplinary team following SCRUM
Internal coordination of the development and UX/UI teams
Requirements engineering with the client

Technical Consultant | Senior Frontend Developer

EUROPA Versicherungen

Complete technical design and coordination of a rate calculator core used to deliver multiple calculators. Defined the architecture and setup, and acted as lead frontend developer for the calculator component:
Development of a web component with Vue2, Vuex, Vue Router, and TypeScript
Micro-frontend approach with Shadow DOM for integration into a Typo3 CMS, which can be enhanced with various properties by the editors
The individual calculators are generated from JSON using a custom-developed form generator
Automated UI tests with Cypress.io

Performance Analyst

Ford Kögler GmbH

Performance audit focused on optimizing Google Web Vitals
I transformed the data collected from the analysis tools into plain language for the stakeholders and provided it with corresponding action plans for the development team
Definition of performance budgets and goals
Web Vitals scores improved by 30% after the initial measures

Lead Frontend Developer | Solution Architect

HABA Group B.V. & Co.KG

PWA website connected to the headless CMS Contentful via GraphQL
Implemented as SSG (Static Site Generation) with Next.js and TypeScript
Deployment via serverless hosting, including serverless functions (FaaS) with Vercel
Performance optimization focused on Google's Core Web Vitals metrics
Implementation following agile methods and Scrum Master responsibilities

Lead Frontend Developer | Frontend Architect

HDI Versicherung

Sub-project:
Micro-frontend approach for integrating a search function into the existing HDI intranet
Frontend implementation with Vue 3 as a web component using the Composition API and store management
Main project:
Responsive frontend relaunch of the HDI websites, landing pages, and intranet based on HTML, SASS, and vanilla JavaScript ES6
Set up the complete frontend boilerplate, including Webpack, linter, Git, and CI/CD
A monorepo approach was used to enable the reuse of individual components, and the npm packages were hosted in the internal Nexus repository to prevent redundancies and manage module versions
Automatic generation of an online style guide with Storybook

Senior Frontend Developer

MEDION AG

Frontend implementation (HTML, CSS, ESS) for MEDION's SAP Hybris online shop
Coordination with the backend development team and integration of the frontend components into the JSP templates
Online style guide with Storybook

IT Consultant | Senior Frontend Developer

Sportcast GmbH

SPA relaunch of the DFL media portal with AngularJS
Development of a custom video player based on JW Player, with the option to mark individual scenes and keyframes so they could then be ordered
Communication with the middleware via a REST API and documentation with Swagger
Technical consultant and lead frontend developer. Coordination of the five-person development team

Senior Frontend Developer

Steiff Retail GmbH

Responsive Magento e-commerce shop implementation with the JavaScript framework Vue.js and the headless frontend commerce platform Vue Storefront
Adyen was configured and integrated in the frontend as the payment service provider. This required developing new API endpoints in the Magento backend, which then communicate with the headless frontend via a REST interface
Automated integration tests with Cypress.io

Native App Developer

ZEG / Eurorad

Development of an app for a bike rental system based on NativeScript and Angular for iOS and Android
Geolocation and geotracking services for billing based on the distance traveled
Bluetooth LE (BLE) integration for app-controlled bike lock functionality

Senior Frontend Developer

brandung GmbH & Co. KG

Headless implementation of the agency website with React
TYPO3 CMS as the backend and communication via a REST API

Senior Frontend Developer

porta Möbel Online Shop GmbH & Co. KG

Frontend implementation (HTML, CSS, ESS) for the SAP Hybris online shops of Porta and SB Möbel Boss
Coordination with the backend development team and integration of frontend components into the JSP templates
Online style guide with Storybook

Industry experience

See where this freelancer has spent most of their professional time.

Experienced in Information Technology, Professional Services, Media and Entertainment, Arts and Crafts, Advertising, and Sport.

Information Technology

Professional Services

Media and Entertainment

Arts and Crafts

Advertising

Sport

Business area experience

See which departments and functions this freelancer has contributed to most.

Experienced in Information Technology, Product Development, Marketing, Strategy, and Operations.

Information Technology

Product Development

Marketing

Strategy

Operations

Summary

Experienced Senior Fullstack Developer with a focus on frontend and over 20 years of expertise in developing scalable web applications, eCommerce solutions, and enterprise software. Cross-industry experience in fashion, retail, insurance & finance, healthcare, and sports.

Technology focus: JavaScript, TypeScript, Angular, Vue.js, React, Node.js, SEO, and performance optimization.

As an IT Consultant and Solution Architect, I support companies in planning, architecting, and implementing complex software and eCommerce projects, with a focus on requirements engineering, technical concepts, and business feasibility.

Skills

Javascript, Typescript
Angular, Vue2, Vue3, Nuxt.Js
React, Next.Js
Graphql, Rest
Html5, Css, Sass, W3c, Wcag
Aws, Serverless
Performance Analysis, Seo
Consulting And Technical Concept Development

Languages

German

Advanced

English

Advanced

Education

Oct 2000 - Jun 2001

SAE Institute

BA (SAE) Multimedia Producer · Web-/Multimedia Management and Producer · Cologne, Germany

Statistics

Experience

Total positions 27

Experience in Information Technology 28.5 y

Avg length 1 y 6 m

Longest experience 4 y 11 m

Expertise

Recent roles Fullstack Developer, Solution Architect, Performance Analyst, Frontend Developer

Main industries Information Technology, Professional Services, Media and Entertainment

Main business areas Information Technology, Product Development, Marketing

Qualifications

Highest degree Bachelor

Profile

Member since

September 2026

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Frequently asked questions

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Simon is based in Overath, Germany and can operate in on-site, hybrid, and remote work models.

Simon speaks the following languages: German (Advanced), English (Advanced).

Simon has at least 29 years of experience. During this time, Simon has worked in at least 13 different roles and for 10 different companies. The average length of individual experience is 2 years and 10 months. Note that Simon may not have shared all experience and actually has more experience.

Based on recent experience, Simon would be well-suited for roles such as: Fullstack Developer, Solution Architect, Performance Analyst, Frontend Developer.

Simon's most recent position is Fullstack Developer at RTL Technology GmbH.

In recent years, Simon has worked for RTL Technology GmbH, CPlus - Vetworking, No-Code/Low-Code, Fressnapf Tiernahrungs GmbH, KMH GmbH, and Self-employed / Freelance.

Simon is most experienced in industries like Information Technology, Professional Services, and Media and Entertainment. Simon also has some experience in Arts and Crafts, Advertising, and Sport.

Simon is most experienced in business areas like Information Technology, Product Development, and Marketing. Simon also has some experience in Strategy and Operations.

Simon has recently worked in industries like Information Technology, Media and Entertainment, and Retail.

Simon has recently worked in business areas like Information Technology, Product Development, and Strategy.

Simon holds a Bachelor in Web-/Multimedia Management and Producer from SAE Institute.

Simon is immediately available part-time for suitable projects.

Daily rate distribution

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<€480 €480-640 €640-800 €800-960 €960-1120 €1120+

The rates shown represent the typical market range for freelancers in this position based on recent contracts on our platform.

Average rates for similar positions

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Daily rate avg. 810 €

The average daily rate is the mean of all daily rates from recent contracts of comparable freelancers on our platform.

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Median rate 800 €

The median daily rate is the middle value of all daily rates — half of comparable freelancers charge less, half charge more. Unlike the average, it is barely affected by outliers.

Calculated based on our freelancers’ daily rates as of 16 Sep 2026. Actual rates may vary depending on seniority level, experience, skill specialization, project complexity, and engagement length.