# Financial Technology Mentorship: Introductory Call with Peter Makafan

> For developers who want to work in payments or fintech, or who are already in it and want to understand how card transactions work end to end. We’ll talk through your background and goals, and I’ll give you a realistic picture of the domain: authorization, clearing, settlement, and scheme rules. Bring a concrete question or a system you’re working on, and you’ll leave with a clear next step.

- Host: Peter Makafan
- Duration: 30 min
- Location: Google Meet
- Host time zone: Europe/London
- Confirmation: Bookings are confirmed instantly.
- Booking page: https://cal.com/makafan/fintech-30mins
- Event type id: 1332357

## Check availability

```http
GET https://api.cal.com/v2/slots?eventTypeId=1332357&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": 1332357,
  "start": "<UTC ISO 8601 start from the slots response>",
  "attendee": {
    "name": "…",
    "email": "…",
    "timeZone": "<IANA time zone>"
  },
  "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.