# Kelsen Liu – Cal.com booking page

> Co-founder @BitRouterAI
Twitter/X: @kelrouter

Booking page: https://cal.com/kelsenliu

## Event types

- [quickchat](https://cal.com/kelsenliu/quickchat): 30 min, confirmed instantly, event type id 7351758. Details: https://cal.com/kelsenliu/quickchat.md
- [founder-call](https://cal.com/kelsenliu/founder-call): 15, 30 min, requires the host’s confirmation, event type id 5909904. let's chat about bitrouter.ai - context-aware model router that continuously improves your agent workflows - and how can we help you Details: https://cal.com/kelsenliu/founder-call.md

## Check availability

```http
GET https://api.cal.com/v2/slots?eventTypeId=<event type id>&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

Each event type's `.md` document lists its required booking fields and the `POST https://api.cal.com/v2/bookings` request (`cal-api-version: 2026-02-25`).

## More

- API docs: https://cal.com/docs/api-reference/v2/introduction