# Discovery call with Halfmark Studio

> A free 30-minute video call about your idea, your users and what success looks like. You leave with a clear next step, and if it's a fit, a written proposal with scope, timeline and quote follows.

- Host: Halfmark Studio
- Duration: 30 min
- Location: Cal Video
- Host time zone: Europe/London
- Confirmation: Bookings are confirmed instantly.
- Booking page: https://cal.com/halfmark/discovery
- Event type id: 7729224

## Check availability

```http
GET https://api.cal.com/v2/slots?eventTypeId=7729224&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": 7729224,
  "start": "<UTC ISO 8601 start from the slots response>",
  "attendee": {
    "name": "…",
    "email": "…",
    "timeZone": "<IANA time zone>"
  },
  "guests": [
    "guest@example.com"
  ],
  "bookingFieldsResponses": {
    "Company-or-website": "…",
    "What-would-you-like-to-build": "…",
    "When-would-you-like-to-start": "…",
    "notes": "…",
    "How-did-you-hear-about-us": "…"
  }
}
```

- Required fields: `name` (Your name), `email` (Email address), `Company-or-website` (Company or website), `What-would-you-like-to-build` (What would you like to build?), `When-would-you-like-to-start` (When would you like to start?)
- Optional fields: `guests` (Add guests), `notes` (Additional notes), `How-did-you-hear-about-us` (How did you hear about us?)
- `name` and `email` go in `attendee` and `guests` is a list of emails; every other field goes in `bookingFieldsResponses` under its name.