# Let's work together - 20 min intro with Leszek Lammel

> Hi, let's get to know each other and see if there's fit. I am an GTM engineer and the Founder of Lammel Advisory where we help B2B teams scale their pipeline. We build the strategy, the CRM setup and the campaigns as one system, so the right accounts get the right message and every reply lands with the right rep.

- Host: Leszek Lammel
- Duration: 20 min
- Location: Google Meet
- Host time zone: Europe/Warsaw
- Confirmation: Bookings are confirmed instantly.
- Booking page: https://cal.com/leszek-lammel-advisory/20min
- Event type id: 5412446

## Check availability

```http
GET https://api.cal.com/v2/slots?eventTypeId=5412446&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": 5412446,
  "start": "<UTC ISO 8601 start from the slots response>",
  "attendee": {
    "name": "…",
    "email": "…",
    "timeZone": "<IANA time zone>"
  },
  "guests": [
    "guest@example.com"
  ],
  "bookingFieldsResponses": {
    "notes": "…",
    "The-minimal-ticket-to-work-together-is--5k---month--Is-this-in-your-budget-range": "…"
  }
}
```

- Required fields: `name` (Your name), `email` (Work email), `notes` (What are you hoping to get out of this meeting?), `The-minimal-ticket-to-work-together-is--5k---month--Is-this-in-your-budget-range` (The minimal ticket to work together is $5k / month. Is this in your budget range?)
- Optional fields: `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.