Orhan Keskin - Freelance Java Software Developer

Q: Where is Orhan based?

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

Q: What languages does Orhan speak?

Orhan speaks the following languages: English (Advanced), Turkish (Advanced), German (Elementary) .

Q: How many years of experience does Orhan have?

Orhan has at least 7 years of experience. During this time, Orhan has worked and for 7 different companies . The average length of individual experience is 1 year and 11 months . Note that Orhan may not have shared all experience and actually has more experience.

Q: What companies has Orhan worked for in recent years?

In recent years, Orhan has worked for kv.digital GmbH , Brenntag , and Private project .

Q: Which industries is Orhan most experienced in?

Orhan is most experienced in industries like Information Technology (IT) , Healthcare , Media, and Entertainment and Publishing . Orhan also has some experience in Metals and Mining , Energy , and Pharmaceutical .

Q: Which business areas is Orhan most experienced in?

Orhan is most experienced in business areas like Information Technology (IT) , Product Development , and Marketing . Orhan also has some experience in Project Management and Logistics .

Q: Which industries has Orhan worked in recently?

Orhan has recently worked in industries like Healthcare , Information Technology (IT) , and Chemical .

Q: Which business areas has Orhan worked in recently?

Orhan has recently worked in business areas like Information Technology (IT) and Product Development .

Q: What is Orhan's education?

Orhan attended Dortmund University of Applied Sciences and Arts .

Q: Does Orhan have any certificates?

Orhan has 3 certificates . These include: PMI – PMP Certified , Project Management Professional , and SCJP Sun Certified Java Programmer .

Recommended expert

Hemer, Germany

Experience

Aug 2022 - Sep 2024

2 years 2 months

kv.digital GmbH

Backend development for appointment and doctor services, including implementing various requirements for managing doctor appointments.
SCRUM/Kanban
Java 21
IntelliJ Idea
SpringBoot (MVC, Data JPA, …)
GIT
Confluence
JIRA
Maven
CI: Jenkins
Docker
ActiveMQ
MariaDB
Solr
Liquibase
Testcontainer
JUnit5
Mockito

May 2022 - Aug 2022

4 months

Brenntag

Development work and technical consulting on software for recipe order processing.
Technical consulting and implementation of pricing software for chemical substances.
Java 11
IntelliJ Idea
SpringBoot (MVC, Data JPA, …)
GIT
Maven
Solr
Vaadin
MsSQL
Docker
Azure DevOps

Oct 2021 - Feb 2022

5 months

Private project

Private app development with Jetpack Compose to learn the Kotlin programming language.

Feb 2021 - Sep 2021

8 months

kv.digital GmbH

Development of the vaccination appointment service for kv.digital GmbH.
Responsible for backend development of the vaccination appointment service, including implementing vaccination guidelines and managing vaccination appointments for doctors.
SCRUM/Kanban
Java 11
IntelliJ Idea
SpringBoot (MVC, Data JPA, …)
GIT
Confluence
JIRA
Maven
CI: Jenkins
Docker
MariaDB
Solr
Liquibase
JUnit5
Mockito

Nov 2018 - Oct 2020

2 years

Private solo development of a mobile game app

Led and solo-developed a mobile game.
Solely responsible for development and coordination of freelancers to obtain assets (graphics, sound, music, marketing).
Used the LibGDX hybrid game framework for cross-platform development.
Successfully launched the app on the Google Play Store and iOS App Store in November 2020.

Mar 2018 - Oct 2018

8 months

Vaillant Group

Development and implementation of microservices to manage and control remotely operated heating systems.
Performing data analysis of specific events such as failures, malfunctions and power consumption.
SCRUM
Java 8
IntelliJ Idea
SpringBoot
Microservices
GIT
JIRA
Maven
CI: Jenkins
Docker
MariaDB
Kafka
JUnit5
Mockito

Mar 2017 - Aug 2017

6 months

Bayer

Development and implementation of backend microservices to control remotely operated heating systems.
Analysis and evaluation of specific events such as failures, malfunctions and power consumption to optimize system performance.
SCRUM
Angular 2
HTML 5
CSS
Java 8
IntelliJ Idea
SpringBoot
GIT
Maven
CI: Jenkins
MongoDB
Solr
JUnit5
Mockito

Feb 2016 - Dec 2016

11 months

thyssen krupp steel

Development of a component for the manufacturing execution system in the warehouse management area.
SCRUM
Java 8
Eclipse
Hibernate
GIT
Maven
CI: Jenkins
Oracle

Industries Experience

See where this freelancer has spent most of their professional time. Longer bars indicate deeper hands-on experience, while shorter ones reflect targeted or project-based work.

Experienced in Information Technology (4.5 years), Healthcare (2.5 years), Media and Entertainment (2 years), Metals and Mining (1 year), Chemical (0.5 years), and Energy (0.5 years).

Information Technology

Healthcare

Media and Entertainment

Metals and Mining

Chemical

Energy

Business Areas Experience

The graph below provides a cumulative view of the freelancer's experience across multiple business areas, calculated from completed and active engagements. It highlights the areas where the freelancer has most frequently contributed to planning, execution, and delivery of business outcomes.

Experienced in Information Technology (5 years), Product Development (5 years), Marketing (2 years), Project Management (2 years), and Logistics (1 year).

Information Technology

Product Development

Marketing

Project Management

Logistics

Summary

Thank you for your interest. My name is Orhan Keskin, born in 1976. I have been a passionate Java developer for over 24 years and have gained valuable experience in numerous projects. Since 2010, I have been working as a freelance Java software developer with a clear focus on backend development, especially with Spring Boot.

Skills

Java 21
Kotlin
Spring Boot (Web, Data Jpa, Hibernate, Security, Rest, Ai…)
Jsf
Vaadin
Angular
Junit 5
Mockito
Assertj
Restassured
Testcontainers
Jenkins
Docker
Activemq
Git
Maven
Gradle
Solr
Jms
Kafka
Postgres
Mariadb
Mongodb
Ldap
Scrum
Kanban
Intellij Idea
Jira
Confluence
Android Development With Kotlin And Jetpack Compose
Mobile Game Development With Libgdx

Languages

English

Advanced

Turkish

Advanced

German

Elementary

Education

Dortmund University of Applied Sciences and Arts

Diploma in Computer Science (FH) · Dortmund, Germany

Certifications & licenses

PMI – PMP Certified

Project Management Professional

SCJP Sun Certified Java Programmer

Profile

Created

August 2025

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Frequently asked questions

Do you have questions? Here you can find further information.

Where is Orhan based?

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

What languages does Orhan speak?

Orhan speaks the following languages: English (Advanced), Turkish (Advanced), German (Elementary).

How many years of experience does Orhan have?

Orhan has at least 7 years of experience. During this time, Orhan has worked and for 7 different companies. The average length of individual experience is 1 year and 11 months. Note that Orhan may not have shared all experience and actually has more experience.

What companies has Orhan worked for in recent years?

In recent years, Orhan has worked for kv.digital GmbH, Brenntag, and Private project.

Which industries is Orhan most experienced in?

Orhan is most experienced in industries like Information Technology (IT), Healthcare, Media, and Entertainment and Publishing. Orhan also has some experience in Metals and Mining, Energy, and Pharmaceutical.

Which business areas is Orhan most experienced in?

Orhan is most experienced in business areas like Information Technology (IT), Product Development, and Marketing. Orhan also has some experience in Project Management and Logistics.

Which industries has Orhan worked in recently?

Orhan has recently worked in industries like Healthcare, Information Technology (IT), and Chemical.

Which business areas has Orhan worked in recently?

Orhan has recently worked in business areas like Information Technology (IT) and Product Development.

What is Orhan's education?

Orhan attended Dortmund University of Applied Sciences and Arts.

Does Orhan have any certificates?

Orhan has 3 certificates. These include: PMI – PMP Certified, Project Management Professional, and SCJP Sun Certified Java Programmer.

What is the availability of Orhan?

Orhan is immediately available for suitable projects.

What is the rate of Orhan?

Orhan's rate depends on the specific project requirements. Please use the Meet button on the profile to schedule a meeting and discuss the details.