Florian Rubel - Senior Fullstack Developer

Cologne, Germany

Experience

Aug 2024 - Sep 2024

2 months

Senior Fullstack Developer

Ivii GmbH

2-month modernization of a management UI for AI-powered cameras monitoring production processes, migrating from React to Vue.js 3 (freelance).
Ivii GmbH sells AI-supported camera systems that monitor production processes.
Datasets can be trained with a series of images and optimized for a wide variety of components.
The project involved a 2-month improvement of the existing user interface.
A designer provided the new design.
The foundation was a complex React application that had to be rewritten in Vue 3 with SFC.
The backend consisted of multiple microservices based on C# and Python.
My tasks included building the central architecture of the Vue application and its configuration.
Vite was used as the builder.
In addition, Pinia, Router, I18n, ESLint, and Prettier were used.
A special feature was the use of Leaflet.
Although Leaflet is actually a tool for displaying maps, it was used here to draw and display detection zones on images.
Since no sufficiently working Vue implementation existed, I wrote a custom integration.
I also supported the expansion of the backend and extended authentication to meet new requirements.
Technologies used: TypeScript, React, Vue 3, C#, Python, HTML, SVG, Docker, Vite, ESLint, vue-router, vue-i18n, Pinia, Leaflet, SignalR, gRPC

May 2024 - Present

1 year 3 months

Lead Fullstack-Developer

Own commercial project

Development of a management project for cinema operators based on Vue.js 3 in the frontend and C# in the backend.
I can provide insight into the code for this project.
I am still working on my own commercial project, which I cannot describe in detail but can provide technical background information.
The backend is a C# .NET 8 MVC backend that relies heavily on inheritance with generic types to standardize API endpoints and massively reduce code volume.
Each controller has a basic set of actions and can be extended or restricted as needed.
Entity Framework is also used.
For authentication and authorization, we use Microsoft Identity with a role- and claim-based system that can be applied to any endpoint.
Further features include data shaping, over-posting protection, and data model validation.
The frontend is currently implemented with Vue.js 3 and TypeScript and mirrors the same abstraction with classes and generic types in the service layer, which interfaces with the API, to reflect the standardized API endpoints with minimal effort.
We might switch to .NET Blazor Pages in the future.
Parts of this project's code and functionality can be presented.

Nov 2023 - Jun 2024

8 months

Lead Frontend Developer

bezahl.de by NX-Technologies

Modernization of the fintech product from Vue.js 2 to Vue.js 3 and coaching developers (freelance).
The fintech company offers complex and comprehensive payment management for the automotive industry via the bezahl.de platform.
The existing interface for dealers and customers, built with Vue 2, was to be modernized to Vue 3 with TypeScript.
My task was the technical leadership, architecture, and support and mentoring of the team during the new project setup.
A simple migration from Vue 2 to Vue 3 was not possible due to some external dependencies no longer compatible with Vue 3, such as the Buefy component library.
Therefore, the application had to be almost completely redeveloped.
The SFC variant was chosen for components.
Vuetify.js was used as the component library, which we extended and visually adapted with custom components.
At the client's request, we used Pug instead of HTML in the templates.
A special challenge was the complexity and scope of the application, which required deep immersion in the existing solutions.
Connecting and correctly typing the existing REST API endpoints based on Node.js with Express was one of the most complex tasks.
Thematically separated service TypeScript modules were created for each API endpoint, containing all relevant endpoints.
We also made adjustments and extensions to the API.
Technologies used: TypeScript, JavaScript, Vue 2, Vue 3, Node.js, Express, SCSS, Pug, HTML, SVG, Docker

Jul 2023 - Nov 2023

5 months

Senior Frontend Developer

Rohde & Schwarz Cybersecurity

Expansion and modernization of the Vue.js-based product for managing and configuring encryption servers (freelance).
Rohde & Schwarz Cybersecurity develops hardware solutions for encrypting traffic between different corporate networks.
My tasks included supporting the further development of the management software for the hardware solutions and migrating from Vue 2 class-based components to the Vue 3 setup pattern with TypeScript.
A major challenge was the immense size, requiring constant evaluation during modernizations and refactorings whether existing components should be adapted or completely rewritten.
The most complex solution I implemented was a centralized validation mechanism for forms and wizards that mirrored the API validation.
This new mechanism was implemented across the entire project and provided localized error messages before form submission.
All implemented features and bug fixes were extensively tested with the new test framework Vitest.
Technologies used: Vue 3, TypeScript, Vite, SCSS, Node.js, WebSockets, Vitest

Dec 2022 - May 2023

6 months

Lead Senior Fullstack Developer

Talkevent GmbH

Modernization of the existing frontend and backend based on Vue.js and Node.js with Express, as well as conversion from JavaScript to TypeScript (freelance).
Leadership and upskilling of developers in new technologies.
Talkevent develops chat solutions for savings banks, banks, and insurance companies to enable advisors to establish diverse and simple digital contact with customers.
Solutions include text chat, audio chat, video chat, co-browsing, whiteboards, screen sharing, and file sharing.
All conversations can be archived with personal information removed.
My role involved modernizing the frontend and backend.
The backend, implemented with Node.js, Express, and MongoDB with Mongoose, was to be migrated to TypeScript along with updating all dependencies to the latest versions.
All necessary interfaces for Mongoose database models were generated automatically.
The frontend, built with Vue 2, was to be upgraded to Vue 3 with TypeScript and the setup pattern.
All dependencies were updated to the latest versions.
A challenge in both projects was the sheer size, requiring automated solutions or custom scripts (e.g., patch scripts) for many otherwise manual steps.
Technologies used: Vue 3, TypeScript, Vite, SCSS, Node.js, Express, Mongoose, MongoDB, Vitest, WebSockets

Dec 2021 - Nov 2022

1 year

Senior Fullstack Developer

Advellence GmbH

Development of a product data research tool based on Vue 3 and Azure API Management, Azure Functions (C#), Azure Data Factory (freelance).
I was engaged to implement a Vue 3 interface for item research for clinics in the style of an e-commerce platform.
My client was Advellence GmbH, commissioned by Sana Kliniken AG for this project.
I was brought in as a frontend expert but quickly supported backend topics intensively.
The frontend project was initially implemented with Vue 3 Options API, Vue CLI 4, Vue-I18n, Jest, SASS (BEM), Vue Router, and Vuex.
Later, it was modernized by refactoring to the Composition API with SFC Setup Pattern.
Vuex was replaced by Pinia, and Vue CLI was replaced by Vite.
The design came from another agency and was precisely implemented in close collaboration with the designer.
Later, GLUU-based authentication via the OpenID standard was integrated.
All developments were covered by tests using the Jest framework.
High coverage was ensured for all components, services, helpers, views, and stores.
User interactions were simulated in components and results verified.
A switch from Jest to Vitest was planned; I researched and familiarized myself with the new framework, but the budget was not approved.
Another project involved creating CSV exports from the underlying PIM via Azure Data Factory.
My task was to model pipelines and data flows for data transformation and composition.
For large downloads, it was necessary to collect item IDs first, which is not possible client-side due to runtime.
I developed an Azure Logic App that collects up to 500,000 IDs and initiates the client download.
I also supported the team in expanding an internal customer tool for price maintenance, a Vue project fed by Azure Functions (C#).
My tasks included extending the Vue frontend and the C# backend.
Technologies used: C# .NET 6.0, EF Core, Vue 3, TypeScript, Vite, SCSS, Jest, Azure Data Factory, Azure API Management, Azure Functions, Microsoft Cognitive Search

Sep 2021 - Jan 2023

1 year 5 months

Lead Fullstack-Developer

Starbase Nexus

Open-source community project using Vue 3 in the frontend and C# in the backend.
This is an open-source community project based on C# .NET 5 and Vue 3 with TypeScript.
So far, I have written all the code; contributions from other developers can be made in the future.
The goal is to collaborate internationally with developers in an open-source setting and try out new ideas.
The backend is cloud-ready and can scale horizontally.
A database-friendly implementation was chosen because databases are the most costly to scale horizontally, and this is a non-profit project.
Technologies used: C# .NET 5.0, EF Core, Vue 3, TypeScript, Vue CLI, SCSS, Augmented-Ui

Jul 2021 - Feb 2022

8 months

Senior Frontend-Developer

Tivian (formerly Questback)

Development of a dashboard management/admin panel.
This project is an administration interface for the Dashbo project, where administrators can configure dashboard projects and set data sources.
Technically, the frontend is very similar to the aforementioned project, using Vue 3 with TypeScript.
Additionally, Tailwind UI and TailwindCSS are used.
The backend is based on Node.js with Express, also using TypeScript.
The REST API is documented via Swagger.
Due to an NDA, I cannot disclose further connected backend technologies.
Both frontend and backend are cloud-ready and operated in AWS Cloud.
Both were covered with Jest tests.
As with the Advellence GmbH project, all areas of the frontend and backend were covered by tests.
A particularly high coverage was ensured, so every testable line of code was tested, including additional negative tests and error handling.
Technologies used: Vue 3, TypeScript, Node.js, Docker, Express, SCSS, TailwindCSS, Tailwind UI

Dec 2020 - Nov 2022

2 years

Senior Fullstack-Developer

As Good as Pros

Development of an app for booking sports events during the COVID period, based on Vue 3 in the frontend and C# in the backend (part-time).
For the young startup, an app with a backend was developed to offer sports events digitally and on-site.
Personal data had to be collected as per COVID regulations.
The app features:
Creation of appointments (online & on-site)
Assignment of trainers/hosts
On-demand billing for appointments or subscriptions
Broadcasting of appointment updates
Transactional emails and push notifications
Social logins (SSO)
Technical components:
The backend is a C# (.NET 5) REST API connected to a MySQL 8 database via EF Core.
The frontend is a Vue 3 (with TypeScript) PWA.
Both frontend and backend are cloud-ready and currently run on an AWS EC2 instance but can be moved to a container service with autoscaling.
Push notifications are delivered via SignalR over WebSockets, including action-triggered and scheduled notifications.
An automated service sends transactional emails.
Technologies used: C# .NET 5.0, EF Core, Vue 3, TypeScript, Vue CLI, SCSS, PWA, PayPal Checkout, PayPal Subscriptions, Stripe, Service Worker, SignalR, WebSockets

Nov 2019 - Sep 2021

1 year 11 months

Senior Frontend-Developer

Tivian (formerly Questback)

Development of a dashboard application (DASHBO) (employed from 2019-11 to 2021-02).
Dashbo is a Tivian (formerly Questback) product that presents statistical data for employee feedback programs on clear and simple dashboards.
The goal was to replace Tableau, which was too complex and expensive for many use cases.
The frontend is built with Vue 2 (class-based components) and, except for the Vue Tours extension, is a completely custom development.
Subtle animations and accessible color choices ensure a great user experience.
A theming option allows users to set custom colors, for example, matching corporate identity.
The backend is implemented in Node.js with TypeScript and Express as a REST API.
Apache Kafka is used for quick data connectivity to underlying feedback databases.
The entire project (frontend & backend) is designed for the cloud without being tied to a specific cloud provider to maximize flexibility.
Technologies used: Vue 2, TypeScript, Node.js, Docker, Express, SCSS

Sep 2019 - Apr 2021

1 year 8 months

Lead Fullstack-Developer

Hyperion Headquarters

C# study project for a community website with over 7,000 active members at the time.
This was my first large C# study project to gain practical experience in a real project.
The scenario revolves around the community around the MMO Dual Universe.
At peak times, up to 10,000 active users were online.
The project had over 7,000 registered users.
I provided various services and products to simplify the gaming experience, including:
CDN with file upload, image & video optimization & processing
Media gallery
Recursive crafting calculator
Ship catalog (product catalog)
Data comparison tools
JWT role-based authentication/authorization
SSO with Discord
GitLab SSO integration
NodeBB SSO integration
The backend was built with C# ASP.NET Core 3.1.
The REST API standard is used and automatically documented with Swagger.
MySQL 8 is used as the database.
The frontend was built with Vue 2 (Options API).
For styling, I used SASS (SCSS) with BEM to ensure long-term maintainability.
For image and video optimization, I worked in C# with the ImageMagick and FFmpeg libraries.
The project is hosted on an Ubuntu 18.04 Hetzner root server.
Technologies used: C# ASP.NET Core 3.1, EF Core, Vue 2, TypeScript, Vue CLI, SCSS, ImageMagick, FFmpeg, GitLab, NodeBB, Discord OAuth2

Mar 2014 - May 2019

5 years 3 months

Senior Fullstack-Developer

CHRONEXT

Development of a shop system and fulfillment tool for a luxury watch online shop, as well as leading the shop team (employed).
As the lead E-Commerce developer, I developed the entire shop system until May 2019.
The backend was a custom implementation based on the Slim Framework, initially with PHP 5.6, later updated to 7.1.
MySQL 5.7 was used as the database.
Algolia was integrated for product search, a service that provides high-performance searches at scale, backed by Elasticsearch and MongoDB, and AI-supported.
Since modern frontend frameworks like Nuxt and Next were not yet established, the frontend was server-side rendered and enhanced with jQuery for dynamic elements.
Major challenges included high SEO requirements (metadata, Google structured data, sitemap generation, etc.) and integrating external tracking tools and payment providers (PayPal, Finetrade, SOFORTÜberweisung, etc.).
Additionally, monitoring and administration tools for the shop system were built in the backend with Symfony 4 and Laravel and in the frontend with Vue 2 (Options API).
Product data management was also implemented with these technologies, primarily developed by me.
Technologies used: PHP 5.6–7.1, jQuery, Vue 2, Slim Framework, Symfony 4, Laravel, PayPal, Google Analytics, Facebook API, CrazyEgg, FineTrade, SOFORTÜberweisung, anti-fraud tools, SCSS, BEM, MySQL 5, Algolia

Jul 2013 - Mar 2014

9 months

Fullstack-Developer

inVentiv Health

Development of websites for the pharmaceutical industry about medications and treatment methods based on TYPO3 (employed).
Earlier in my career, I worked for two agencies and primarily implemented small to medium projects for various clients.
These were usually TYPO3-based projects with PHP, SCSS (SASS), JavaScript, jQuery, and MySQL.
Most were corporate or product websites.
Technologies used: PHP 5, jQuery, SCSS (SASS), TYPO3, JavaScript

Oct 2010 - Jun 2013

2 years 9 months

Junior Fullstack-Developer

FH-Konzept

Development of websites for various clients such as Schwank, JG Gruppe, Sikkens Joinery, etc., based on TYPO3 (employed).
Earlier in my career, I worked for two agencies and primarily implemented small to medium projects for various clients (including Schwank, JG Gruppe, Sikkens Joinery, etc.).
These were usually TYPO3-based projects with PHP, SCSS (SASS), JavaScript, jQuery, and MySQL.
Most were corporate or product websites.
Technologies used: PHP 5, jQuery, SCSS (SASS), TYPO3, JavaScript

Summary

I am a Fullstack Developer with over 14 years of professional experience. Through my career path and freelancing, I have gained many insights into various industries and companies, as well as their teams and, above all, people. In this process, I have been active not only as a developer in the front- and backend areas, but I have also gained some leadership experience.