# Marcel R. G. Berger – Cal.com booking page

> Software architect, 20+ years. I build apps and run them myself.

For companies: as The App Architect I build, take over or rescue apps and then run them, fully looked after. The accounts stay in your name, and the code sits in your repository from day one. Book the Initial call (English) or the Erstgespräch (German), in urgent cases the 15-minute Urgent call / Eiltermin. theapparchitect.com

For engineers: the Dev chat is thirty minutes of shop talk, free, no project enquiries. marcelrgberger.com

Conversations in German or English. Contracting party for client work: DigitalFreedom Global LLC.

Booking page: https://cal.com/marcelrgberger

## Event types

- [Eiltermin (15 Min.)](https://cal.com/marcelrgberger/eiltermin): 15 min, confirmed instantly, event type id 7375824. Nur für dringende Fälle, zum Beispiel • Ihre App fällt aus oder stürzt ab, • eine Store-Frist läuft bald ab, oder • ein Kunde braucht kurzfristig Ihre Antworten auf einen Sicherheitsfragebogen. 15 Minuten: Sie schildern die Lage, wir legen den nächsten Schritt fest. Für alles andere buchen Sie bitte das kostenlose Erstgespräch (30 Min.). Sie sprechen direkt mit Marcel. Kostenlos und unverbindlich. — The App Architect ist eine Marke der DigitalFreedom Global LLC. Impressum · Datenschutz Details: https://cal.com/marcelrgberger/eiltermin.md
- [Urgent call (15 min)](https://cal.com/marcelrgberger/urgent-call): 15 min, confirmed instantly, event type id 7375823. For urgent cases only, for example • your app is down or crashing, • a store deadline is about to expire, or • a customer needs your answers to a security questionnaire at short notice. 15 minutes: you describe the situation, we agree on the next step. For everything else, please book the free initial call (30 min). You talk to Marcel directly. Free, no obligation. — The App Architect is a brand of DigitalFreedom Global LLC. Imprint · Privacy Details: https://cal.com/marcelrgberger/urgent-call.md
- [Erstgespräch (30 Min.)](https://cal.com/marcelrgberger/erstgespraech): 30 min, confirmed instantly, event type id 7372542. Ihre App läuft. Um den Rest kümmere ich mich. Dieses Gespräch ist für Firmen ohne eigenes Technikteam: Ihr Entwickler ist weg, ein KI-Prototyp soll live gehen, der Store hat Ihre App abgelehnt, ein Kunde prüft Sie als Lieferanten, oder Sie planen eine neue App. So läuft das Gespräch: • Erzählen Sie, was passiert ist. In Ihren Worten, Technikwissen brauchen Sie nicht. • Gemeinsam klären wir den nächsten Schritt: meist ein App-Check, manchmal gleich Übernahme, Rettung oder Neubau, dazu Budget und Zeitrahmen in groben Zügen. • Am Ende haben Sie einen klaren, schriftlichen nächsten Schritt. Ohne Vorbereitung, ohne Verkaufsgespräch, unverbindlich. Teams mit eigener IT sind ebenfalls willkommen; bei mehreren Systemen oder einer Investitionsentscheidung ist der nächste Schritt meist ein Architektur-Review. Sie sprechen direkt mit Marcel, dem Architekten, der für Ihre App verantwortlich ist. Festpreise für jeden Schritt: theapparchitect.com/de/preise — The App Architect ist eine Marke der DigitalFreedom Global LLC. Impressum · Datenschutz Details: https://cal.com/marcelrgberger/erstgespraech.md
- [Dev chat (30 min)](https://cal.com/marcelrgberger/talk-with-marcello): 30 min, confirmed instantly, event type id 6649024. Let us talk shop. Not a project call, no pitch, no slides. Two engineers talking about what they are building and which decision is currently giving them trouble. Topics I enjoy: • Architecture and system design • Java and Quarkus on Kubernetes • Native iOS and Flutter • Identity, access and security • AI in development: where it helps and where it only adds noise Client projects are not part of this call; they run through The App Architect: initial call (30 min). No preparation needed. Just bring whatever you are working on. Free. — marcelrgberger.com Imprint · Privacy Details: https://cal.com/marcelrgberger/talk-with-marcello.md
- [Conference Talk — Scoping Call](https://cal.com/marcelrgberger/conference-talk): 30 min, confirmed instantly, event type id 5722022. Free 30-minute scoping call for a conference talk, internal company event, or meetup. Topics I speak on: • AI in software development • App development — native Apple and cross-platform • Building scalable Kubernetes systems solo • Indie development and running a solo software business • Open to suggestion What I build: marcelrgberger.com Book: Solopreneur — The Art of Working Alone This call is for scoping the talk: format, audience, length, date, logistics. The actual talk is delivered as a separate engagement. — Honorarium: €2.000 net per delivered talk. Invoice issued after the talk. Travel, accommodation, and meals are arranged and paid by the booking organization. The 30-minute scoping call itself is free. Invoiced by DigitalFreedom Global LLC (Wyoming, USA). Prices exclude tax. Business customers in the EU account for VAT under the reverse-charge procedure. Any other local tax is the customer's responsibility. Imprint · Privacy Details: https://cal.com/marcelrgberger/conference-talk.md
- [Initial call (30 min)](https://cal.com/marcelrgberger/consultation): 30 min, confirmed instantly, event type id 4335893. Your app runs. I take care of the rest. This call is for companies without their own tech team: your developer is gone, an AI prototype has to go live, the store rejected your app, a customer is reviewing you as a supplier, or you are planning a new app. How the call works: • Tell me what happened. Plain words, no tech knowledge needed. • Together we work out the next step: usually an App Check, sometimes a takeover, a rescue or a new build straight away, with a rough budget and timeline. • You leave with a clear written next step. No prep, no pitch, no obligation. Teams with their own IT are welcome too; for several systems or an investment decision the next step is usually an Architecture Review. You talk to Marcel directly, the architect who will be accountable for your app. Fixed prices for every step: theapparchitect.com/pricing — The App Architect is a brand of DigitalFreedom Global LLC. Imprint · Privacy Details: https://cal.com/marcelrgberger/consultation.md

## Check availability

```http
GET https://api.cal.com/v2/slots?eventTypeId=<event type id>&start=YYYY-MM-DD&end=YYYY-MM-DD&timeZone=<IANA time zone>
cal-api-version: 2024-09-04
```

The response is `{"data":{"YYYY-MM-DD":[{"start":"<ISO 8601 with offset>"}]}}`; no API key is needed.

## Book

Each event type's `.md` document lists its required booking fields and the `POST https://api.cal.com/v2/bookings` request (`cal-api-version: 2026-02-25`).

## More

- API docs: https://cal.com/docs/api-reference/v2/introduction