# Your payment set-up with Ramon Helwegen with Ramon Helwegen

> Thirty minutes with Ramon Helwegen, founder of EcomStream. Bring your provider names, your annual volume and your markets. That is enough to see where you stand, in cost, in performance, or in the construction of the contract. You will hear where the upside sits before anything is proposed.

- Host: Ramon Helwegen
- Duration: 30 min
- Location: MS Teams
- Host time zone: Europe/Amsterdam
- Confirmation: Bookings are confirmed instantly.
- Booking page: https://cal.com/ecomstream/payment-set-up
- Event type id: 6770182

## Check availability

```http
GET https://api.cal.com/v2/slots?eventTypeId=6770182&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": 6770182,
  "start": "<UTC ISO 8601 start from the slots response>",
  "attendee": {
    "name": "…",
    "email": "…",
    "timeZone": "<IANA time zone>"
  },
  "guests": [
    "guest@example.com"
  ],
  "bookingFieldsResponses": {
    "company": "…",
    "annual-payment-volume": "…",
    "notes": "…"
  }
}
```

- Required fields: `name` (Your name), `email` (Email address), `company` (Company), `annual-payment-volume` (Annual payment volume)
- Optional fields: `notes` (Your current provider or providers, and the markets you sell in (optional)), `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.