# Erstgespräch - efficientoptics.com with Jakob Eppelsheim

> Buchen Sie ein unverbindliches Erstgespräch für eine erste Bestandsaufnahme Ihres Geschäfts. Nennen Sie mir gerne vorab auch Ihre aktuelle Website in der Notizenbox. Ich rufe Sie auf der angegeben Telefonnummer an. Viele Grüße, Jakob Eppelsheim 089 248 85 900 efficientoptics.com

- Host: Jakob Eppelsheim
- Duration: 45 min
- Location: Attendee phone number
- Host time zone: Europe/Berlin
- Confirmation: Bookings are confirmed instantly.
- Booking page: https://cal.eu/efficientoptics.com/refra
- Event type id: 351439

## Check availability

```http
GET https://api.cal.eu/v2/slots?eventTypeId=351439&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.eu/v2/bookings
cal-api-version: 2026-02-25
Content-Type: application/json

{
  "eventTypeId": 351439,
  "start": "<UTC ISO 8601 start from the slots response>",
  "attendee": {
    "name": "…",
    "email": "…",
    "timeZone": "<IANA time zone>"
  },
  "location": {
    "type": "attendeePhone",
    "phone": "…"
  },
  "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.
- `location` is required: `location.phone` is the attendee’s own.