Premium App Development for B2B & Scaling Startups

Diagnosis. Architecture. Scale.

I make complex IT projects tangible. As a specialized tech partner, I translate your business goals and user needs into high-performance, intuitive full-stack apps. Focused, transparent, and at the highest technical level.

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Paul Köhler – Senior App Development in Hamburg for B2B & Startups with Flutter & Serverpod

B2B Companies

Digitalization of complex business processes through custom full-stack solutions

Scale-ups & Startups

Fast MVPs & Prototypes – investment-efficient and with maximum ROI

Tech Teams & Agencies

Senior Flutter expertise for targeted scaling of your development capacities

Holistic Expertise: From Strategy to Scaling

As a full-stack partner, I handle more than just coding. I ensure a well-thought-out architecture, a user-centric frontend, and a backend that guarantees you full control.

Discovery & Architecture Workshop

Every successful project starts with the right diagnosis. In a compact workshop, we evaluate your requirements, assess technical risks, and I translate complex IT questions into understandable business decisions. The result: A crystal-clear roadmap.

Flutter Development & MVPs

Whether it's a fast prototype for market validation or a complex enterprise app: With Flutter, I develop high-performance, cross-platform applications for iOS, Android, and Web. A shared codebase ensures maximum investment efficiency and fast time-to-market.

Backend, APIs & Data Sovereignty

Custom backends with Serverpod or Firebase. The focus is on real-time functions, seamless API integration (payments, maps, etc.), and maximum control. With Serverpod, you host your own infrastructure – for maximum data security and zero vendor lock-in.

DevOps, Testing & Code Quality

Good code proves itself in live operation. I ensure clean software architecture (Clean Code), automated tests, and robust, Docker-based deployments. This keeps your app maintainable, stable, and ready for scaling user numbers.

A structured path to launch

1. Diagnosis & Deep Dive

I don't just accept requirements, I ask "Why". We clarify technical feasibility, examine the business case, and define a future-proof architecture.

2. UX/UI & Prototyping

Good design starts with the user. I translate complex workflows into a clear, intuitive frontend. If needed, I bring in experts from my network for visual design.

3. Full-Stack Development

Implementation with the highest quality standards ("Clean Code"). An efficient ecosystem (Dart) for frontend (Flutter) and backend (Serverpod). Transparent and test-driven.

4. Launch & Scaling

Your product goes live. I ensure stable deployment and monitoring with persistence and endurance, performing reliably long after the launch.

Project Highlight

A look into my work: From complex full-stack solutions to agile prototypes.

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Yourny Travel & Leisure

Full-Stack mobile app development with Flutter and Serverpod for a travel platform – including booking logic, payment integration, real-time features, and DevOps setup.

Technologies Used

Flutter

Dart

Sentry

Firebase

Serverpod

PostgreSQL

GPT

Docker

Frontend / App

Flutter/Dart Development Mobile app development with BLoC state management
Backend & Cloud Services Serverpod integration, Firebase (Auth, Analytics, Remote Config), and real-time communication
Mobile Platform Expertise Deep linking, push notifications, and platform-specific integrations
UI/UX & Localization Custom design system, animations, localization, and OpenStreetMap integration
DevOps & Quality Code generation, integration testing, and error tracking with Sentry

Backend / Server

Dart & Serverpod Backend development with real-time functionality
PostgreSQL & External APIs Database management with 3 million hotel datasets, Google Places, Mollie (payments), and Firebase authentication
Travel Industry Expertise Hotel booking workflows, multi-participant vacation planning, payment processing, and accommodation search systems
DevOps & Cloud Docker containerization, VPS deployment, environment management, and Sentry monitoring
Performance & Scalability Database optimization, parallel processing, and large-scale data synchronization for hotel information

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Who I am

I am Paul – passionate Flutter developer, strategic thinker, and problem solver. My approach: deep technical understanding (Clean Code, Flutter, Serverpod) paired with a strong focus on people.

Customers appreciate that I don't give up even on difficult topics ("grit"), translate complex IT matters understandably, and always think from the end-user's perspective. You work directly with me as a senior developer – which means 100% focus, high quality standards, and direct knowledge transfer.

Reliability & Speed

You don't get an agency structure, but direct implementation – with experience, empathy, and focus.

Full-Stack from a Single Source

Frontend with Flutter, backend with Serverpod or Firebase – including DevOps, testing & monitoring.

Business Understanding

I understand how product development works – and help you build digital products with real added value.

Remote or in Hamburg

I work remotely – but upon request also on-site in Hamburg or surrounding area.

Skills

Favorite

Flutter

Expert

Favorite

Serverpod

Expert

Favorite

Dart

Expert

Favorite

BLoC

Expert

Favorite

Firebase

Expert

Docker

Proficient

Git

Proficient

VPS

Proficient

Databases

Proficient

Testing

Proficient

Product

Proficient

MVP

Proficient

Prototyping

Proficient

AI

Proficient

Architecture

Proficient

Scrum

Proficient

Java

Proficient

TypeScript

Proficient

Astro

Proficient

SolidJS

Proficient

Angular

Proficient

Redux

Proficient

NestJS

Proficient

Node.js

Proficient

What colleagues & partners say

"Paul has the rare gift of maintaining an objective and confident overview of even complex IT topics and explaining them clearly."

— Christof v. B.

"A very reliable developer with a strong focus on usability. Paul understands extremely quickly how customers actually use an app and translates that into a clear, intuitive frontend."

— Stephan F.

"Paul doesn't just accept things, he asks: 'What's behind it?'. This curiosity and the ability to see connections distinguish him."

— Mirja S.

"He has a deep technical understanding, solves complex problems soundly, and doesn't give up even during long dry spells. He bites through."

— Damian B.

Let's talk about your project

Do you have an app idea, an ongoing project, or open questions? Let's talk without obligation. I listen, ask the right questions, and we check if I am the right technical partner for you.

Email

Direct contact for detailed project discussions

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LinkedIn

Professional network and updates about my work

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GitHub

Open source projects and code showcase

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