# SaaS, Mobile app or IoT Development with Rúben Martins

> In this session, we’ll dive into your product idea or technical challenge and outline a fast MVP strategy. I’ll help you define a realistic roadmap, choose the right technologies, and show how I can step in as your fractional CTO — guiding your team from prototype to scale.

- Host: Rúben Martins
- Duration: 30 min
- Location: Google Meet
- Host time zone: Europe/Lisbon
- Confirmation: Bookings are confirmed instantly.
- Booking page: https://cal.com/rubenmartins/mobile-app-or-iot-development
- Event type id: 1857438

## Check availability

```http
GET https://api.cal.com/v2/slots?eventTypeId=1857438&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

```http
POST https://api.cal.com/v2/bookings
cal-api-version: 2026-02-25
Content-Type: application/json

{
  "eventTypeId": 1857438,
  "start": "<UTC ISO 8601 start from the slots response>",
  "attendee": {
    "name": "…",
    "email": "…",
    "timeZone": "<IANA time zone>"
  },
  "guests": [
    "guest@example.com"
  ],
  "bookingFieldsResponses": {
    "notes": "…"
  }
}
```

- Required fields: `name` (Your name), `email` (Email address)
- Optional fields: `notes` (Additional notes), `guests` (Add guests)
- `name` and `email` go in `attendee` and `guests` is a list of emails; every other field goes in `bookingFieldsResponses` under its name.