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App Development · Berlin

App development —
fast,
transparent,
handover-ready.

Flutter development for companies — from idea to the stores, for iOS and Android. One codebase, one developer, no lock-in.

Free intro call See the process ↓
8+ Years Flutter
20+ Apps live
4.7★ Store rating
39M+ Users served
What I build

Every app starts with a clear specification.

Whether you need an iOS app, Android app, or cross-platform solution built — every project starts with a clear spec and ends with a maintainable codebase.

E-Commerce Apps

Shops, product catalogs, and checkout flows that convert — performant and identical on iOS and Android.

PureleiBRACK.CHMediaMarkt/Saturn

Health & Lifestyle

Sensitive data, clear workflows, and a UI that builds trust — from tracking to community.

ON AG ↗ Orthomol

MVP & Prototypes

Test an idea on the market fast — core features first, extensible instead of throwaway.

SnapnextPeqas
Process

Step by step — no lock-in.

Each step has a clear deliverable. You decide after each step whether to continue — no commitment from start to finish.

01

Intro call

30 min · free

We clarify your idea, the rough scope, and whether we're a fit. You get an initial assessment of feasibility and timeline.

You decide if step 2 makes sense.

02

Scope & specification

1–2 weeks

The idea becomes a clear, written specification: features, screens, data model, and a concrete offer with a fixed price or timeline.

You have a binding picture — and can still walk away.

03

Development

Weeks to months

I build in short iterations — you see working builds regularly, give feedback, and always have visibility into progress.

Transparent status in every sprint, no black box.

04

Testing & launch

1–2 weeks

Testing on real devices, store setup, screenshots, and submission. I support the release on Apple and Google until approval.

Your app is live — in both stores.

05

Handover & maintenance

optional · ongoing

Documented, maintainable code is handed over to you or your team. On request, I stay on as a mobile partner with fixed capacity for updates.

You stay independent — maintenance is an option, not an obligation.

Timeline & scope

How long does app development take?

Whether you're building a new app or extending an existing project — the timeline can be estimated early. You'll get a concrete cost estimate in the free intro call.

MVP / Prototype

Market test with core features

3–6 weeks

iOS + Android from one codebase

Full Product

Feature-rich app with integrations

2–4 months

iOS + Android from one codebase

Retainer

Long-term mobile partner

Ongoing

Fixed monthly capacity

Need a concrete cost estimate? Let's clarify in the intro call — free and no-obligation.

Free intro call
Freelancer vs. Agency

Why a freelancer?

Agencies have their strengths — but for focused app development, an experienced freelancer is often the better choice.

FreelancerAgency
Point of contact One person, directlyPM, developer, QA
Who builds? Same developer from spec to launchRotating developers based on availability
Overhead No middleman, no markupPM, office, sales — all priced in
Speed Short paths, fast decisionsCoordination across multiple levels
Handover Documented & maintainable — no lock-inOften designed for follow-up contracts
Testimonials

What clients walk away with.

Wonderful, professional collaboration! K. laid the foundation for our entire mobile app development. Highly recommended!!

Andre Gröschel Andre Gröschel TrippleACode GmbH

Professional, results-oriented, always friendly collaboration. To be recommended without reservation. Thank you, K.!

Timo Mugele Timo Mugele Framegrabber GmbH

K. was a very valued colleague in my department. He was very reliable and always happy to support others in the team.

Andreas Partenhauser Andreas Partenhauser MediaMarktSaturn Technology GmbH
FAQ

What clients want to know upfront.

What does it cost to have an app built?
It depends on scope. An MVP with core features costs significantly less than a mature platform with many integrations. Instead of a flat rate, you get a concrete, project-specific estimate in the free intro call — transparent and traceable.
Do I get an app for iOS and Android?
Yes. Thanks to Flutter, both come from a single codebase. This saves time and budget because features are built and maintained only once — and both platforms stay in sync.
Do I need technical knowledge?
No. I translate your idea into a clear specification and explain every decision in plain language. You make the product decisions, I handle the tech.
What if I need changes after development?
No problem. The code is documented and handed over maintainably — you're not tied to anyone. On request, I support the app on a retainer with fixed monthly capacity for updates and new features.
How are you different from an agency?
You work directly with the developer who builds — no middleman, no markup, short paths. No project management overhead, no rotating contacts, no lock-in after handover.
Can you improve an existing app?
Yes. Whether performance, new features, a redesign, or resolving tech debt — I get into existing Flutter projects and move them forward cleanly.
What should I look for when choosing an app developer?
Experience with your type of app, a clear process, and handover-ready code. Whether they call it coding, developing, or building — the terms mean the same thing. What matters is that architecture, communication, and documentation are solid.
Should I hire a developer or build the app myself?
If app development isn't your core business, building it yourself is rarely cost-effective. An experienced freelancer ships faster, avoids common pitfalls, and hands over a codebase your team can maintain independently — no lock-in.
Do you also handle push notifications and post-launch optimization?
Yes. App development doesn't end at launch — engagement, retention, and smart notification systems are part of the architecture work. I designed a push notification framework for MediaMarktSaturn across 13 countries. Read the full deep dive on how we approached it.
Next step

Ready to bring your app idea to life?

30-minute intro call — free and no-obligation. You'll know afterwards if it's a fit and what your project will cost.

Book intro call