Marcel Berger - Apps and beyond

AI builds MVPs. I build stable apps.

Stable means software that ships, scales to real users, survives the AI hype cycle, and stays maintainable when the team grows or shrinks. The hard part isn't writing code — it's making sure the code you wrote still works in six months without you.

20+ years in software engineering. Before going indie: microservice architectures for banks, IAM systems in regulated industries, instant payment platforms, digital transformation in critical infrastructure (KRITIS). Production-first, secure by default, designed to last.

Single owner — development and operations in one person. Clients: native iOS, native macOS, Flutter. Backends: Quarkus, Kafka, PostgreSQL. Infrastructure: multi-environment Kubernetes (dev / test / prod) with ArgoCD GitOps, autoscaling node pools, S3 object storage, Prometheus and Grafana monitoring, encrypted secret pipelines with integrity verification, runbook-driven incident response, and self-built AI ops agents that keep it all running unattended.

My approach: short cycles, written summaries, direct trade-off conversations. No status meetings without a deliverable, no scope without an exit criterion, no rewrites without a real reason.

Author of Solopreneur — The Art of Working Alone — what it takes to build, ship, and operate products without a team. Open-source Claude Code plugins and command-line tooling for Apple platforms.

I don't outsource. I don't subcontract. I don't pitch what I haven't shipped myself.

Conversations in German or English.

marcelrgberger.com · github.com/marcelrgberger

Initial Consultation

You have an app idea — but want an honest take before you sink time and money into it?

A focused 30-minute conversation. If your idea is realistic, I'll tell you what it actually takes. If it isn't, I'll tell you that too.

Stacks I work in: native iOS (Swift), native macOS, Flutter, Java/JVM.

What I build: github.com/marcelrgberger

Honest, technical, no pitch.

Bring your idea. Leave with clarity.

—

Imprint · Privacy

  • 30m

App Review for Vibe Coders

Built your app with AI tools — and now it's wobbling?

A focused review for vibe coders who shipped fast and need to harden what they built. I'll go through your code, architecture, and operations. You'll leave with a clear list of what's brittle, what's missing, what to keep, what to throw away.

Stacks I work in: native iOS (Swift), native macOS, Flutter, Java/JVM.

What I build: github.com/marcelrgberger

Honest, technical, no pitch.

Rate: €250 net per hour. Billed by actual time — invoice after the session.

Bring your code. Leave with a list.

—

Imprint · Privacy

  • 60m

  • 1

Problem Solver

Stuck on something specific? Bring it. I bring fresh eyes.

A focused 60-minute session on one concrete problem — a slow query, a flaky build, an architecture decision, a tricky bug. You describe it upfront, I prepare, we solve it together on the call.

Stacks I work in: native iOS (Swift), native macOS, Flutter, Java/JVM.

What I build: github.com/marcelrgberger

Honest, technical, no pitch.

Bring a problem. Leave with a path.

—

Rate: €250 net per hour. Invoice after the session.

Billing: minimum of the booked slot — more if the session runs longer. Free cancellation up to 24 hours before the start. Cancellations after that, or no-shows, are billed in full.

Imprint · Privacy

  • 60m

  • 1

Marcel Berger - Apps and beyond | Cal.com