Jürgen Koller - SwiftUI Developer for iOS and macOS

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Heilbronn, Germany

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Experience

Jan 2023 - Present

3 years 11 months

SwiftUI Software Developer

Successfully implemented the complete macOS app 'PDF Content Search' and iOS app 'PDF Cnt Search' from initial concept through final deployment to the App Store.

Jan 2022 - Dec 2022

1 year

Swift Software Developer

Development of a utility app for macOS using Xcode and SwiftUI
Technologies used: OCR, SQLite, cloud services, SwiftNIO
Publication of the app 'PDF Content Search' in the Apple macOS App Store

Jan 2021 - Dec 2022

2 years

Xamarin Frontend Developer

Member of a Scrum team developing an app for accessing household appliances
Implementation of user stories for cloud features through an external cloud service

Jan 2020 - Dec 2021

2 years

Xamarin Software Developer

Collaboration in a 9-member team (frontend, backend, QA, UI/UX) following agile Scrum
Implementation of all upcoming user stories in a Xamarin Forms Shell application for iOS and Android

Jan 2019 - Dec 2020

2 years

Xamarin Software Developer

Sole developer responsible for the complete development and release process of a Xamarin app update with native UI for iOS and Android
Collaboration with a UI designer and project manager

Jan 2018 - Dec 2019

2 years

Xamarin Software Developer

Development of a new mobile client for SAP systems using Xamarin Forms (iOS, Android)
Support for a .NET team of 5 developers in creating a dynamic XAML user interface controlled by Entity Framework

Jan 2018 - Dec 2018

1 year

Xamarin Software Developer

Transfer of an Android app to Xamarin with a shared code base for Android and iOS
Application of MVVM, mobile services, data persistence, and Bluetooth communication
Responsibility for the complete development cycle as the lead developer

Jan 2017 - Dec 2017

1 year

Xamarin Frontend Developer

Introduction of Xamarin expertise to a .NET team (frontend, backend, QA, UI/UX) following agile Scrum
Business area: Augmented reality remote service
Technologies: Xamarin, C#, Xamarin Forms, Visual Studio, Visual Studio Mac, iOS, Android, Windows UWP

Jan 2016 - Dec 2016

1 year

Xamarin Software Developer

Adding new features and fixing bugs in an existing Xamarin Android app with native UI
Business area: Sports and leisure
Technology: Xamarin C#, Xamarin Studio, Android

Jan 2016 - Dec 2016

1 year

Xamarin Software Developer

Development of a new Xamarin app from scratch with native UI for iOS and Android
Backend integration and background services such as GPS tracking
Business area: Logistics and transport
Technology: Xamarin C#, Xamarin Studio, iOS, Android

Jan 2016 - Dec 2016

1 year

Xamarin Software Developer

Migration of a native Windows Phone app to Xamarin with support for iOS, Android and Windows Phone
Planning and execution of the app migration as the sole developer within the specified time and budget
Business area: Logistics and Transport
Technology: Xamarin C#, Xamarin Forms, Xamarin Studio, Visual Studio, iOS, Android, Windows Phone, SQLite, RESTful-Service

Jan 2015 - Dec 2015

1 year

Xamarin Software Developer

Integration of an existing Xamarin Android app with a new backend REST API service
Business area: Sports and Leisure
Technology: Xamarin C#, Xamarin native UI, Xamarin Studio, Android, RESTful-Service, ServiceStack, mopub

Jan 2015 - Dec 2015

1 year

Xamarin Software Developer

Development of a new Xamarin iOS/Android app for citizens to contact government officials
Business area: Citizen Services
Technology: Xamarin C#, Xamarin Forms, Xamarin Studio, Android, iOS, RESTful-Service, Azure Push Notifications

Jan 2014 - Dec 2014

1 year

Xamarin Software Developer

Development of a Xamarin iOS, Android and Windows Store app for BORT medical with 100% offline functionality for product news
Client: BORT GmbH, Germany
Business area: Medical Healthcare
Technology: Xamarin C#, Xamarin native UI, Visual Studio, Xamarin Studio, SQLite, custom data synchronization, offline HTML layout rendering

Jan 2011 - Dec 2013

3 years

Mac Objective-C Developer

Development of a native macOS app in Objective-C for point-to-point data transfer without a cloud service
Business area: Tools and Utilities
Technology: Xcode, Objective-C, CocoaAsyncSocket

Jan 2011 - Dec 2013

3 years

Mac, iOS Objective-C Developer

Development of a native macOS app in Objective-C for photo professionals to easily distribute photos via smartphones
Development of the MacOS server application MyPicServer and the client app MyPic
Business area: Utilities
Technology: Xcode, Objective-C

Jan 2011 - Dec 2012

2 years

Mac, iOS Objective-C Developer

Development of a new iOS app for BORT medical with 100% offline functionality for product news
Business area: Medical healthcare
Technology: Xcode, Objective-C

Industry experience

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

Experienced in Information Technology, Healthcare, Sport, Transportation, and Government and Administration.

Information Technology

Healthcare

Sport

Transportation

Government and Administration

Business area experience

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

Experienced in Information Technology, Product Development, and Logistics.

Information Technology

Product Development

Logistics

Summary

Xamarin / SwiftUI software developer with 13 years of experience in mobile application development and 10 years of experience developing mobile apps with Xamarin technology.

Skills

Swift
Swiftui
.Net Maui (Xamarin)

Languages

German

Native

English

Advanced

Statistics

Experience

Total positions 17

Experience in Information Technology 13 y

Avg length 1 y 7 m

Longest experience 3 y 10 m

Expertise

Recent roles SwiftUI Software Developer, Swift Software Developer, Xamarin Frontend Developer

Main industries Information Technology, Healthcare, Sport

Main business areas Information Technology, Product Development, Logistics

Member since

June 2025

Last update

October 2026

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Frequently asked questions

Have questions? Find more information here.

Jürgen is based in Heilbronn, Germany.

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

Jürgen has at least 16 years of experience. During this time, Jürgen has worked in at least 6 different roles. The average length of individual experience is 1 year and 11 months. Note that Jürgen may not have shared all experience and actually has more experience.

Based on recent experience, Jürgen would be well-suited for roles such as: SwiftUI Software Developer, Swift Software Developer, Xamarin Frontend Developer.

Jürgen's most recent position is SwiftUI Software Developer.

Jürgen is most experienced in industries like Information Technology, Healthcare, and Sport. Jürgen also has some experience in Transportation and Government and Administration.

Jürgen is most experienced in business areas like Information Technology, Product Development, and Logistics.

Jürgen has recently worked in industries like Information Technology.

Jürgen has recently worked in business areas like Information Technology and Product Development.

Jürgen will be available part-time from November 2026.

Daily rate distribution

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<€400 €400-800 €800-1200 €1200-1600 €1600+

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

Rates are based on recent contracts and do not include FRATCH margin.

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Daily rate avg. 925 €

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 960 €

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 6 Nov 2026. Actual rates may vary depending on seniority level, experience, skill specialization, project complexity, and engagement length.