You're seeing this page as if you were . The main menu is still yours, though. Exit from immersion
Karsten KerberKK

Karsten Kerber

Lead Full-Stack & Backend Developer

€720/day
Heilbronn, DE
8-15 years

Average response time: 1 hour

About Karsten

Ich unterstütze Startups und Tech-Unternehmen als hands-on Senior Full-Stack und Backend Developer bei der Entwicklung moderner Softwareprodukte. Mein Schwerpunkt liegt auf Python/FastAPI-Backends, REST APIs, PostgreSQL-Datenmodellen, Flutter-Apps und cloudnahen Deployments.

In meiner Rolle als CTO eines Health-Tech-Startups habe ich unter anderem eine neue Datenbank- und Backend-Architektur geplant und mit dem Team umgesetzt. Ziel war es, die bestehende Plattform stabiler, performanter und besser erweiterbar zu machen. Zusätzlich war ich für die Weiterentwicklung einer modularen App-Architektur verantwortlich, damit neue Anforderungen schneller und sauberer umgesetzt werden können.

Besonders gerne arbeite ich mit Startups und schnell wachsenden Unternehmen, bei denen pragmatische Lösungen, saubere technische Entscheidungen und schnelle Umsetzung wichtig sind. Ich bringe dabei nicht nur Entwicklungserfahrung mit, sondern auch ein gutes Verständnis für Produkt, Architektur, Deployment und Teamprozesse.
  • German

    Native or bilingual

  • English

    Fluent

Can work on-site
Heilbronn (up to 50km), München (up to 50km), Stuttgart (up to 50km), Heidelberg (up to 50km), Frankfurt am Main (up to 50km)

Experience

  • Doctos GmbH
    Lead Software Developer + CTO
    May 2023 - Today (3 years and 2 months)
    München, Germany

    Full-Stack & Backend Development

    • Developed backend systems with Python/FastAPI and C#/.NET for a healthcare SaaS product used by dental practices

    • Built REST APIs, data models, integrations, and workflows for documentation, billing, and practice-management features
    • Worked hands-on across backend, frontend, mobile, infrastructure, and automation

    IT Infrastructure & Architecture

    • Planned and led a modern IT infrastructure, including database design, API structures, integrations, deployments, and operations
    • Designed and maintained complex PostgreSQL database structures
    • Led the migration from a self-hosted setup to a Kubernetes production environment on STACKIT
    • Worked with Docker deployments, CI/CD workflows, and production processes

    Speech Recognition & AI

    • Integrated Azure Speech Service into a voice-based documentation and billing application for dental practices
    • Implemented pre- and post-processing of audio data to improve transcription quality
    • Reduced speech recognition error rates to below 5%
    • Built AI-driven workflows that transform spoken input into structured documentation and billing output

    App & Web Development

    • Developed a modular Flutter application with native packages for iOS using Swift and Windows using C++
    • Built and maintained internal CMS functionality and admin tools with Angular
    • Contributed to features across mobile, web, backend, and API layers

    Robotic Process Automation

    • Enhanced a C#-based RPA application for automating Windows applications and manual workflows

    • Improved automation logic, reliability, and maintainability

    Technical Leadership

    • Shaped the technical roadmap, software architecture, and development priorities
    • Organized development processes using Scrum and Kanban
    • Recruited, onboarded, and mentored developers
    • Provided code reviews, technical guidance, and performance feedback
    • Managed priorities, timelines, and delivery in a fast-moving startup environment
    PostgreSQL Python GO Angular Flutter
  • marpinion GmbH + minnt GmbH
    Software Developer
    February 2018 - July 2022 (4 years and 5 months)
    München, Germany
    • Developed and maintained hybrid apps with Xamarin for medical professionals (physicians, pharmacists)
    • Built WCF Web Services and backend logic
    • Created and maintained an Angular-based CMS
    • Modernized IT infrastructure by migrating to Microsoft Azure (DevOps)
  • teamsports.ai
    Lead Software Developer
    August 2022 - April 2023 (9 months)
    Berlin, Germany
    • Continued development of a sports-focused Flutter app, introducing new features and optimizing performance
    • Refactored a native Android/iOS "Family and Groups Organizer" app to Flutter
    • Established a new developer mobile team, defining processes for continuous development cycles and ensuring streamlined collaboration

Recommendations

Be the first to recommend Karsten

Help this freelancer shine by sharing your experience working together.

These freelancer profiles also match your criteria

AgathaA

Agatha Frydrych

Backend Java Software Engineer

4.7

(3)

2

BaptisteB

Baptiste Duhen

Fullstack developer

4.6

(4)

5

AmedA

Amed Hamou

Senior Lead Developer

4

(2)

7

AudreyA

Audrey Champion

Web developer

4.3

(3)

4

Education

  • Bachelor's Degree in Business Informatics,
    University of Applied Sciences
    2017
    Bachelor's Degree in Business Informatics,
  • Software Engineering studies,
    Heilbronn University
    2009
    Software Engineering studies,

Skill set

Categories