Full-Stack Software-Entwicklung. Technologien u.a.: Kotlin, Java, Spring, Typescript, React, PostgresQL, Kubernetes
Aktualisiert am 26.03.2024
Profil
Freiberufler / Selbstständiger
Remote-Arbeit
Verfügbar ab: 01.10.2024
Verfügbar zu: 80%
davon vor Ort: 20%
Analytisches Denken
Teamfähigkeit
Selbstständigkeit
Hohe Frustrationstoleranz
Hoher Qualitätsanspruch
Aufgeschlossenheit und Lernbereitschaft
Kotlin
Java
Spring
ReactJS
TypeScript
PostgreSQL
Kafka
Kubernetes
German
Muttersprache
English
C2

Einsatzorte

Einsatzorte

Hamburg (+50km) Stade (+150km)

Ich arbeite bevorzugt remote, reise aber innerhalb Deutschlands (und ggf. darüber hinaus) auch gern zu gelegentlichen Vor-Ort-Terminen an.

möglich

Projekte

Projekte

1 Jahr 11 Monate
2020-09 - 2022-07

Online appointments booking

Software developer Kotlin Spring Kafka ...
Software developer

Fielmann provides a platform where it?s customers can book appointments with any of their roughly 700 branches. When booking an appointment the customer expects to be directed to their closest (or most familiar) branch that provides the kind of service, they require. Those services can relate to glasses, contact lenses and hearing aids. On the other hand the employees in the branches have to be able to attend to all their customers which include not only the ones who booked an appointment but also walk-in customers.

This complex platform which consists in part of third-party solutions was run, maintained and constantly improved by the team that I was part of.

  • Contribution to refinement of user requirements, architectural decision making and implementation planning

  • Development of a migration tool to migrate a third-party platform to a newer version

  • Improvement of the existing appointments application throughout the entire technology stack

  • Testing, monitoring and operating of the system

  • Various technical migrations regarding the hosting platform and the CI/CD environment (e.g. from Concourse to Github Actions, Kubernetes to EKS)

  • Training and onboarding of new staff members

  • Documentation and knowledge sharing


Kotlin Spring Kafka GraphQL Postgres React AWS Kubernetes Helm Grafana Prometheus Concourse Github Actions Docker
Fielmann AG
Hamburg
1 Jahr 4 Monate
2019-03 - 2020-06

Product Catalogue

Software developer Kotlin Spring Typescript ...
Software developer

The Fielmann AG has almost 700 branches in Germany and other countries. Since it is impossible for each branch to have all of the several thousand articles (sunglasses and corrective frame models) on location, there was the desire to have a digital catalogue of the company's products. This should allow opticians and customers to browse through the portfolio, check the current price and availability of the glasses models and order them from the central disposition warehouse.

Throughout my participation in this project I came to be the most senior developer on the team which lead to my critical involvement in all aspects of the software development. Furthermore I was ? at a later stage in the project ? the main contact person for all technical and functional aspects of the software. More specifically my tasks included:

  • Contribution to refinement of user requirements, architectural decision making and implementation planning

  • Contribution to the development of the catalogue application throughout the entire technology stack

  • Configuration and maintenance of technologies for operation, deployment and monitoring

  • Communication with adjacent teams regarding interfaces, data delivery strategies, organisational collaboration and technological exchange

  • Writing documentation and training/onboarding of new team members

  • Performing basic analysis of input data using Python and Jupyter Notebook.

Kotlin Spring Typescript React Kafka AWS Kubernetes Helm Docker Concourse Bash Python Prometheus Grafana
Fielmann AG
Hamburg
8 Monate
2018-06 - 2019-01

MicroService infrastructure and coaching

Software developer and coach Java 8 Dropwizard MongoDB ...
Software developer and coach

An insurance company is in the process of modernizing their internal software development. One of the goals is to train their developers to build microservices on a modern Java technology stack and to deploy them on their OpenShift environment. This training as well as the development and maintenance of example microservices is done by the "infrastructure and coaching team".


As part of the infrastructure and coaching team my tasks were:

  • Developing example microservices including automated tests

  • Coaching and assisting other developers in the development of microservices

  • Discussing principal questions regarding software architecture and deployment processes to find an optimal general solution for the company

  • Improving the given build and deployment pipeline in Jenkins

  • Improving libraries commonly used in the company

  • Adding features to existing productive services


Java 8 Dropwizard MongoDB Jenkins OpenShift Docker Angular JMockit
Hamburg
10 Monate
2017-07 - 2018-04

Online marketing tools

Java Spring (Boot) Mockito ...

Size of team:

12

Project objective:

The team develops and maintains three larger software tools and a number of micro services that are used internally by the online marketing team at OTTO. These tools are used for SEO, SEA and to supply product data to price comparison portals.

My tasks:

I mainly work on the SEO solution which basically crawls the otto.de online shop for product category pages and generates reports for the SEO managers which then use the data to optimize the SEO content of the pages. My involvement stretches throughout the entire development process (Scrum): requirement analysis, planning, development of new features as well as improvement and refactoring of existing code.

 

Main challenges:

  • Complex functional logic
  • Performance optimization
  • (Code) quality assurance
  • (Unit) testing

 

Since the team has decided to migrate one of said tools to AWS, I have familiarized myself with a few of their services, including Cloudformation, ECS, EC2, S3.

Java Spring (Boot) Mockito MongoDB JavaScript Gradle Jenkins IntelliJ GitLab YourKit AWS
OTTO GmbH
3 Monate
2017-04 - 2017-06

Customer portal prototype

TypeScript Angular Ngrx ...

Size of team:

12-15 (partially remote)

Project objective:

The goal was to re-implement parts of the customer portal of a mobile communication reseller.

My tasks:

  • Development of the frontend in Angular
  • Automatic frontend testing using Jasmine/Karma
  • Structuring the architecture of the frontend project in collaboration with the team

TypeScript Angular Ngrx RxJS Jasmine Karma Hybris Docker
Mobilcom/Debitel
Büdelsdorf, Germany
5 Monate
2016-11 - 2017-03

Production Data Management tool

Spring Boot Spring Data Rest Angular ...

Size of team:

3

Project objective:

From-scratch development of a web application to manage information regarding the production process and the quality assurance of produced parts.

My tasks:

  • Participation in requirement analysis workshops with the customer
  • Design of data model
  • Implementation of both backend and frontend
  • Automatic frontend testing using Proctactor

Spring Boot Spring Data Rest Angular PostgreSQL Maven Docker Protractor
ZF Group
Kassel Germany
3 Monate
2016-08 - 2016-10

User Portal for online game

Java Dropwizard Jersey ...

Size of team:

6

Project objective:

This project’s goal was to create a web platform that provides additional features and information (e.g. highscores and statistics) to an online game. To this end the game server output data to a PostgreSQL database which the backend application of this project consumed. Our application would process this data, restructure it for our needs and perform calculations on it. The results were then written to an ElasticSearch instance. The web frontend would then display this data.

My tasks:

  • Extending the existing backend service by API endpoints to be consumed by the frontend
  • Development of backend logic to calculate and generate data needed by the frontend
  • Development of import processes that would first retrieve data from the PostgreSQL database and then transform and persist the data in ElasticSearch
  • Bugfixes, refactoring, testing
  • Analysis and discussion of development strategy with the team
Java Dropwizard Jersey Jackson PostgreSQL ElasticSearch SVN VirtualBox
Protofy

Aus- und Weiterbildung

Aus- und Weiterbildung

March 2004 ? August 2009

Computer Science (Diploma)

Grade: 2,4

Karlsruhe University of Applied Sciences, Germany

  

October 2000 ? September 2003

Computer Science
Aborted without degree, then changed to University of Applied Sciences

University of Karlsruhe (now KIT), Germany

Position

Position

Fullstack developer with a focus on backend
Can contribute to all stages of the development process from the analysis and discussion of functional requirements, architectural decision making, programming and testing to operations and maintenance

Kompetenzen

Kompetenzen

Top-Skills

Analytisches Denken Teamfähigkeit Selbstständigkeit Hohe Frustrationstoleranz Hoher Qualitätsanspruch Aufgeschlossenheit und Lernbereitschaft Kotlin Java Spring ReactJS TypeScript PostgreSQL Kafka Kubernetes

Produkte / Standards / Erfahrungen / Methoden

Work experience 

June 2016 ? April 2018

Position: Software Developer

Customer: FLAVIA IT-Management GmbH, Kassel

Tasks:

Various software projects varying in size, functionality and technologies.

Main Technologies:

Java, Spring, Angular, MongoDB, Elastic Search, PostgreSQL

Sectors:

Gaming, telecommunications, e-commerce, online marketing

 

October 2015 ? December 2015

Sabbatical

  

April 2013 ? October 2015

Position: Software Developer

Customer: BrandMaker GmbH, Karlsruhe

Tasks

First year:

Improvement of a WebShop (Java, JBoss 4 u. 7, Struts, MySQL, MSSQL, Torque, JSP, JavaScript, ExtJS, JUnit, Maven).

As of second year: customer specific solutions and product adaptations, system integration tools and BI reports (same technologies as in 1st year, plus SOAP, REST, JPA/Hibernate, JasperServer)

Sector:

Marketing Resource Management Software

 

December 2009 ? December 2012

Position: Research assistant

Customer: KIT ? Institute for technology and management in construction, Karlsruhe

Tasks

Research project:

SECURITY2People. Development of the fundamentals for a holistic information system for crisis managers and implementation of a prototype. Development of a software component to evaluate data from social media. Project management and coordination, publications, presentations.

Sector:

Research in IT

 

March 2010 ? March 2011

Position: Assistant lecturer (secondary employment)

Customer: University of Applied Sciences Karlsruhe

Tasks:

First year lectures "Theoretical computer science I and II"

Sector:

Education

 

March 2008 ? August 2008

Position: Student apprentice

Customer: Delcam plc, Small Heath Business Park, Birmingham

Tasks:

Localization of graphical user interfaces for the German market. Translation of software documentation from English into German

Sector:

CAD/CAM Software

Social skills

  • Ample experience working in teams and communicating with end users
  • Experience in training and supervising student assistants
  • Conducting job interviews
  • Holding presentations and lectures with audiences of up to 40 people
  • Holding presentations in English
  • Working with an international customer on location in Asia
  • First aider

 

Organizational / managerial skills

  • High degree of personal responsibility and reliability
  • Experience in managing a small research project (at KIT)
  • Coordination of work with external partners
  • Temporary substitute for my team leader

Einsatzorte

Einsatzorte

Hamburg (+50km) Stade (+150km)

Ich arbeite bevorzugt remote, reise aber innerhalb Deutschlands (und ggf. darüber hinaus) auch gern zu gelegentlichen Vor-Ort-Terminen an.

möglich

Projekte

Projekte

1 Jahr 11 Monate
2020-09 - 2022-07

Online appointments booking

Software developer Kotlin Spring Kafka ...
Software developer

Fielmann provides a platform where it?s customers can book appointments with any of their roughly 700 branches. When booking an appointment the customer expects to be directed to their closest (or most familiar) branch that provides the kind of service, they require. Those services can relate to glasses, contact lenses and hearing aids. On the other hand the employees in the branches have to be able to attend to all their customers which include not only the ones who booked an appointment but also walk-in customers.

This complex platform which consists in part of third-party solutions was run, maintained and constantly improved by the team that I was part of.

  • Contribution to refinement of user requirements, architectural decision making and implementation planning

  • Development of a migration tool to migrate a third-party platform to a newer version

  • Improvement of the existing appointments application throughout the entire technology stack

  • Testing, monitoring and operating of the system

  • Various technical migrations regarding the hosting platform and the CI/CD environment (e.g. from Concourse to Github Actions, Kubernetes to EKS)

  • Training and onboarding of new staff members

  • Documentation and knowledge sharing


Kotlin Spring Kafka GraphQL Postgres React AWS Kubernetes Helm Grafana Prometheus Concourse Github Actions Docker
Fielmann AG
Hamburg
1 Jahr 4 Monate
2019-03 - 2020-06

Product Catalogue

Software developer Kotlin Spring Typescript ...
Software developer

The Fielmann AG has almost 700 branches in Germany and other countries. Since it is impossible for each branch to have all of the several thousand articles (sunglasses and corrective frame models) on location, there was the desire to have a digital catalogue of the company's products. This should allow opticians and customers to browse through the portfolio, check the current price and availability of the glasses models and order them from the central disposition warehouse.

Throughout my participation in this project I came to be the most senior developer on the team which lead to my critical involvement in all aspects of the software development. Furthermore I was ? at a later stage in the project ? the main contact person for all technical and functional aspects of the software. More specifically my tasks included:

  • Contribution to refinement of user requirements, architectural decision making and implementation planning

  • Contribution to the development of the catalogue application throughout the entire technology stack

  • Configuration and maintenance of technologies for operation, deployment and monitoring

  • Communication with adjacent teams regarding interfaces, data delivery strategies, organisational collaboration and technological exchange

  • Writing documentation and training/onboarding of new team members

  • Performing basic analysis of input data using Python and Jupyter Notebook.

Kotlin Spring Typescript React Kafka AWS Kubernetes Helm Docker Concourse Bash Python Prometheus Grafana
Fielmann AG
Hamburg
8 Monate
2018-06 - 2019-01

MicroService infrastructure and coaching

Software developer and coach Java 8 Dropwizard MongoDB ...
Software developer and coach

An insurance company is in the process of modernizing their internal software development. One of the goals is to train their developers to build microservices on a modern Java technology stack and to deploy them on their OpenShift environment. This training as well as the development and maintenance of example microservices is done by the "infrastructure and coaching team".


As part of the infrastructure and coaching team my tasks were:

  • Developing example microservices including automated tests

  • Coaching and assisting other developers in the development of microservices

  • Discussing principal questions regarding software architecture and deployment processes to find an optimal general solution for the company

  • Improving the given build and deployment pipeline in Jenkins

  • Improving libraries commonly used in the company

  • Adding features to existing productive services


Java 8 Dropwizard MongoDB Jenkins OpenShift Docker Angular JMockit
Hamburg
10 Monate
2017-07 - 2018-04

Online marketing tools

Java Spring (Boot) Mockito ...

Size of team:

12

Project objective:

The team develops and maintains three larger software tools and a number of micro services that are used internally by the online marketing team at OTTO. These tools are used for SEO, SEA and to supply product data to price comparison portals.

My tasks:

I mainly work on the SEO solution which basically crawls the otto.de online shop for product category pages and generates reports for the SEO managers which then use the data to optimize the SEO content of the pages. My involvement stretches throughout the entire development process (Scrum): requirement analysis, planning, development of new features as well as improvement and refactoring of existing code.

 

Main challenges:

  • Complex functional logic
  • Performance optimization
  • (Code) quality assurance
  • (Unit) testing

 

Since the team has decided to migrate one of said tools to AWS, I have familiarized myself with a few of their services, including Cloudformation, ECS, EC2, S3.

Java Spring (Boot) Mockito MongoDB JavaScript Gradle Jenkins IntelliJ GitLab YourKit AWS
OTTO GmbH
3 Monate
2017-04 - 2017-06

Customer portal prototype

TypeScript Angular Ngrx ...

Size of team:

12-15 (partially remote)

Project objective:

The goal was to re-implement parts of the customer portal of a mobile communication reseller.

My tasks:

  • Development of the frontend in Angular
  • Automatic frontend testing using Jasmine/Karma
  • Structuring the architecture of the frontend project in collaboration with the team

TypeScript Angular Ngrx RxJS Jasmine Karma Hybris Docker
Mobilcom/Debitel
Büdelsdorf, Germany
5 Monate
2016-11 - 2017-03

Production Data Management tool

Spring Boot Spring Data Rest Angular ...

Size of team:

3

Project objective:

From-scratch development of a web application to manage information regarding the production process and the quality assurance of produced parts.

My tasks:

  • Participation in requirement analysis workshops with the customer
  • Design of data model
  • Implementation of both backend and frontend
  • Automatic frontend testing using Proctactor

Spring Boot Spring Data Rest Angular PostgreSQL Maven Docker Protractor
ZF Group
Kassel Germany
3 Monate
2016-08 - 2016-10

User Portal for online game

Java Dropwizard Jersey ...

Size of team:

6

Project objective:

This project’s goal was to create a web platform that provides additional features and information (e.g. highscores and statistics) to an online game. To this end the game server output data to a PostgreSQL database which the backend application of this project consumed. Our application would process this data, restructure it for our needs and perform calculations on it. The results were then written to an ElasticSearch instance. The web frontend would then display this data.

My tasks:

  • Extending the existing backend service by API endpoints to be consumed by the frontend
  • Development of backend logic to calculate and generate data needed by the frontend
  • Development of import processes that would first retrieve data from the PostgreSQL database and then transform and persist the data in ElasticSearch
  • Bugfixes, refactoring, testing
  • Analysis and discussion of development strategy with the team
Java Dropwizard Jersey Jackson PostgreSQL ElasticSearch SVN VirtualBox
Protofy

Aus- und Weiterbildung

Aus- und Weiterbildung

March 2004 ? August 2009

Computer Science (Diploma)

Grade: 2,4

Karlsruhe University of Applied Sciences, Germany

  

October 2000 ? September 2003

Computer Science
Aborted without degree, then changed to University of Applied Sciences

University of Karlsruhe (now KIT), Germany

Position

Position

Fullstack developer with a focus on backend
Can contribute to all stages of the development process from the analysis and discussion of functional requirements, architectural decision making, programming and testing to operations and maintenance

Kompetenzen

Kompetenzen

Top-Skills

Analytisches Denken Teamfähigkeit Selbstständigkeit Hohe Frustrationstoleranz Hoher Qualitätsanspruch Aufgeschlossenheit und Lernbereitschaft Kotlin Java Spring ReactJS TypeScript PostgreSQL Kafka Kubernetes

Produkte / Standards / Erfahrungen / Methoden

Work experience 

June 2016 ? April 2018

Position: Software Developer

Customer: FLAVIA IT-Management GmbH, Kassel

Tasks:

Various software projects varying in size, functionality and technologies.

Main Technologies:

Java, Spring, Angular, MongoDB, Elastic Search, PostgreSQL

Sectors:

Gaming, telecommunications, e-commerce, online marketing

 

October 2015 ? December 2015

Sabbatical

  

April 2013 ? October 2015

Position: Software Developer

Customer: BrandMaker GmbH, Karlsruhe

Tasks

First year:

Improvement of a WebShop (Java, JBoss 4 u. 7, Struts, MySQL, MSSQL, Torque, JSP, JavaScript, ExtJS, JUnit, Maven).

As of second year: customer specific solutions and product adaptations, system integration tools and BI reports (same technologies as in 1st year, plus SOAP, REST, JPA/Hibernate, JasperServer)

Sector:

Marketing Resource Management Software

 

December 2009 ? December 2012

Position: Research assistant

Customer: KIT ? Institute for technology and management in construction, Karlsruhe

Tasks

Research project:

SECURITY2People. Development of the fundamentals for a holistic information system for crisis managers and implementation of a prototype. Development of a software component to evaluate data from social media. Project management and coordination, publications, presentations.

Sector:

Research in IT

 

March 2010 ? March 2011

Position: Assistant lecturer (secondary employment)

Customer: University of Applied Sciences Karlsruhe

Tasks:

First year lectures "Theoretical computer science I and II"

Sector:

Education

 

March 2008 ? August 2008

Position: Student apprentice

Customer: Delcam plc, Small Heath Business Park, Birmingham

Tasks:

Localization of graphical user interfaces for the German market. Translation of software documentation from English into German

Sector:

CAD/CAM Software

Social skills

  • Ample experience working in teams and communicating with end users
  • Experience in training and supervising student assistants
  • Conducting job interviews
  • Holding presentations and lectures with audiences of up to 40 people
  • Holding presentations in English
  • Working with an international customer on location in Asia
  • First aider

 

Organizational / managerial skills

  • High degree of personal responsibility and reliability
  • Experience in managing a small research project (at KIT)
  • Coordination of work with external partners
  • Temporary substitute for my team leader

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