# Intro call with Viacheslav Nikolaev

> Free, no pitch. Tell me what you're building and where it's stuck — I'll tell you what I'd do first, whether or not we work together.

- Host: Viacheslav Nikolaev
- Duration: 30 min
- Location: Google Meet
- Host time zone: Europe/Prague
- Confirmation: Bookings are confirmed instantly.
- Booking page: https://cal.com/nikviac/30min
- Event type id: 6789383

## Check availability

```http
GET https://api.cal.com/v2/slots?eventTypeId=6789383&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": 6789383,
  "start": "<UTC ISO 8601 start from the slots response>",
  "attendee": {
    "name": "…",
    "email": "…",
    "timeZone": "<IANA time zone>"
  },
  "guests": [
    "guest@example.com"
  ],
  "bookingFieldsResponses": {
    "Language-of-the-call": "…",
    "Where-is-the-product-now": "…",
    "notes": "…",
    "Link": "…"
  }
}
```

- Required fields: `name` (Your name), `email` (Email address), `Language-of-the-call` (Language of the call), `Where-is-the-product-now` (Where is the product now?), `notes` (What should I know before the call?)
- Optional fields: `Link` (Link), `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.