# Demo with David Firmin

> Ein kurzer Überblick über gasvisor – Kernfunktionen, Anwendungsfälle und wie es Ihr CO2 Flaschenmanagement vereinfacht.

- Host: David Firmin
- Duration: 30, 45, 60 min
- Location: MS Teams
- Host time zone: Europe/Berlin
- Confirmation: Bookings are confirmed instantly.
- Booking page: https://cal.com/gasvisor-david/30min
- Event type id: 5978957

## Check availability

```http
GET https://api.cal.com/v2/slots?eventTypeId=5978957&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": 5978957,
  "start": "<UTC ISO 8601 start from the slots response>",
  "lengthInMinutes": 30,
  "attendee": {
    "name": "…",
    "email": "…",
    "timeZone": "<IANA time zone>"
  },
  "guests": [
    "guest@example.com"
  ],
  "bookingFieldsResponses": {
    "Name-Ihrer-Firma": "…",
    "attendeePhoneNumber": "…",
    "notes": "…"
  }
}
```

- Required fields: `Name-Ihrer-Firma` (Name Ihrer Firma), `name` (Your name), `email` (E-Mail Adresse)
- Optional fields: `attendeePhoneNumber` (Phone number), `notes` (Zusätzliche Notizen), `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.
- `lengthInMinutes` picks one of 30, 45, 60; pass the same value to the slots request as `duration`.