# Konstantin Tarkus – Cal.com booking page

> I’m a principal engineer and software architect with 20+ years of experience helping startups ship fast without creating long-term pain. I build clear architectures, production-ready MVPs, and reliable AI-powered systems.

I’ve created open-source tools used by thousands of developers, including React Starter Kit and WS-Kit.

If you want help designing your system, speeding up delivery, or integrating AI in a safe, practical way, book a session. Let’s make your next release smoother.

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

## Event types

- [15 Min Meeting](https://cal.com/koistya/15min): 15 min, confirmed instantly, event type id 349329. Have a quick question or want to see if we're a good fit? This 15-minute introductory call is a great place to start. Details: https://cal.com/koistya/15min.md
- [30 Min Meeting](https://cal.com/koistya/30min): 30 min, confirmed instantly, event type id 349328. Let's take a look at your codebase together. In this 30-minute session, I'll identify key areas for optimization and provide actionable feedback. Details: https://cal.com/koistya/30min.md
- [60 Min Meeting](https://cal.com/koistya/60min): 60 min, confirmed instantly, event type id 608598. Need to tackle a complex challenge? In this 60-minute deep dive, we'll work through your architecture, DevOps, or AI tooling to find the best path forward. Details: https://cal.com/koistya/60min.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