Jonas Schalck, Full-stack Developer in Strasbourg, France
Jonas Schalck

Full-stack Developer in Strasbourg, France

Member since September 28, 2021
Jonas is a passionate full-stack mobile developer; he loves everything about programming, from researching to scripting, designing, and building solutions for clients. Using his favorite technologies, he single-handedly developed a social networking application that is now in production. Thanks to his work experience as a manager, Jonas demonstrates excellent soft skills, making communicating with him a painless process.
Jonas is now available for hire


  • Navarc
    Python, Flask, Google Cloud Platform (GCP), Firebase, BigQuery, PostgreSQL...
  • Zappr
    Python, Django, Android, Flutter, NGINX, Kubernetes, Firebase, Dart...
  • Zalando
    Management, Change Management, Leadership, Team Leadership...



Strasbourg, France



Preferred Environment

Ubuntu, Android Studio, PyCharm

The most amazing...

...project I've developed is Zappr, a fully functional social network mobile application.


  • Lead Full-stack Developer | CTO

    2021 - 2022
    • Completely redesigned the database architecture into a simpler model.
    • Refactored the back end from scratch into a cleaner, maintainable project.
    • Optimized and managed the infrastructure alone. Along with the two previous measures, this led to a decrease in infrastructure costs of 70%.
    • Introduced best practices, including a proper Gitflow, documentation, and test suite.
    • Code reviewed all pull requests and provided thorough follow-up feedback to ensure the growth of team members.
    • Guided all feature-related decisions to ensure technical efficiency and optimal UI/UX.
    Technologies: Python, Flask, Google Cloud Platform (GCP), Firebase, BigQuery, PostgreSQL, TypeScript, Devtron, Argo CD, REST APIs, SQLAlchemy
  • Co-founder and Full-stack Developer

    2019 - 2021
    • Designed the app structure to allow scaling and included all features of a complete social networking application, such as image and video caching and preloading, push notifications, an integrated camera, and a chat.
    • Developed and debugged the complete application alone.
    • Shipped the application into production on Android and iOS and deployed the back-end containerized apps into a Kubernetes environment.
    Technologies: Python, Django, Android, Flutter, NGINX, Kubernetes, Firebase, Dart, Full-stack, WebSockets, REST APIs, Django REST Framework, iOS, Swift
  • Area Manager

    2017 - 2019
    • Created KPIs during the ramp-up phase of a new Zalando logistics warehouse.
    • Created and implemented processes that improved productivity and quality delivered as well as the co-workers' safety.
    • Managed 150 to 200 people, including disciplinary responsibility. The objective was to permanently maintain and improve the co-workers' motivation by performing monthly feedbacks and advancement.
    • Planed and coordinated FTEs to optimally achieve the goals and guarantee transparent communication with internal and external partners.
    • Created and programed ad-hoc software in Python, JavaScript (used in Google Sheets), and VBA according to my firm's needs.
    Technologies: Management, Change Management, Leadership, Team Leadership, Lean Project Management, Lean, Process Management, Python, Python 3, JavaScript, Google Sheets, Google Sheets API, Excel VBA
  • Teaching Fellow

    2016 - 2016
    University of Strasbourg
    • Provided lectures in controlling as a teaching fellow at the University of Strasburg for 4th-semester students.
    • Created new exercises and tests covering specific topics.
    • Assessed mid-term tests and final exams as part of my role.
    Technologies: Controlling, University Teaching
  • Freelance Developer

    2015 - 2015
    • Developed a tailor-made database management software programmed in VBA for a client used by around 200 users.
    • Organized meetings with end users in order to define the project specifications. Established an FAQ and step-by-step tutorial covering all functionalities of the application.
    • Provided six months warranty (e.g., bug fixing) and end-user training of key users.
    Technologies: Excel VBA
  • Assistant Project Manager

    2014 - 2015
    Daimler AG
    • Assisted the project manager in his daily tasks during the pre-project phase of the plant's migration towards a new ERP (SAP). Tasks included implementing the SAP project throughout all its essential phases, milestones, workshops, and meetings.
    • Took care of financial issues and summarized the expenses for internal reporting purposes.
    • Supervised the call for tenders, analyzed various offers to select the ideal service provider, and drafted the project's contract.
    • Wrote a thesis which aimed at analyzing the plant's situation in terms of change management, a field in which I made several recommendations.
    Technologies: Project Management Office (PMO), Change Management
  • PMO Intern

    2014 - 2014
    Hugo Boss
    • Coordinated new orders coming from the Benelux of France autonomously to construct Hugo Boss shops and stores.
    • Calculated cost estimations according to benchmarks and assisted cost and invoice control.
    • Ordered via SAP and organized transportation of shop components.
    • Created cross-departmental tools to automate cost extensive administrative tasks in Excel VBA and more generally solved any Excel-related problem.
    Technologies: Project Management Office (PMO), Excel VBA


  • Zappr

    A complete social networking application that was written with Flutter. The API back end is written in Python using the Django framework.

    I was the sole developer on the project, which means I had to manage every step of the process, from designing its structure to shipping it into production.


  • Languages

    Python, Dart, Excel VBA, Python 3, Kotlin, JavaScript, TypeScript, Java, Swift
  • Frameworks

    Django, Flutter, Flask, Django REST Framework
  • Libraries/APIs

    Django ORM, REST APIs, SQLAlchemy, Google Sheets API
  • Tools

    Android Studio, PyCharm, GitHub, BigQuery, NGINX, Google Sheets
  • Paradigms

    Change Management, Management
  • Platforms

    Ubuntu, Android, Firebase, Kubernetes, Google Cloud Platform (GCP), iOS
  • Storage

  • Other

    Leadership, Team Leadership, Lean Project Management, Lean, Full-stack, Devtron, WebSockets, Process Management, Controlling, University Teaching, Project Management Office (PMO), Argo CD


  • Master's Degree in Business Administration
    2010 - 2015
    EM Strasbourg Business School - Strasbourg, France

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