Kotlin Meetup - Utrecht: Pair Programming with AI & Type Safe Tax Calculations

Hello, Kotlin enthusiasts!

Our next NLKUG meetup is happening on March 19th at the adesso Office, located at Wonderwoods, Jaarbeursboulevard 294, 3521BC Utrecht! Join us for an evening filled with 2 great talks, networking, and a lively panel discussion on some of the hottest topics in the Kotlin community.

This event is RSVP-only, and seats are limited to 60 attendees, so be sure to secure your spot early. You can also let us know if you have any dietary preferences when you RSVP.

This meetup is a collaboration between adesso, bol and Flock. bringing together some of the best minds in the industry. A big thank you to our fantastic partners for making this event possible!

📍 Location:
adesso Office, Wonderwoods, Jaarbeursboulevard 294, 3521BC Utrecht

🕒 Timeline:
17:00 – Doors open
17:30 – Dinner 🍕
18:25 – Welcome 🎙️
18:30 - Akif: Pair Programming with AI 💻
19:15 - Break
19:30 - Pim: Type Safe Tax Calculations 💻
20:15 - Networking and Drinks 🍻

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Talk 1: Pair Programming with AI: Building Software in the Age of Coding Agents
Mehmet Akif Tütüncü - Engineer @ bol

AI coding agents are rapidly changing how we write software, but what does that look like in a real Kotlin project?

In this session, I'll share my experience building an open-source Kotlin DSL library primarily by pair programming with AI. After defining the core design by hand, I relied heavily on coding agents to expand features, refactor code, generate tests, draft documentation, automate publishing, and explore alternative designs.

The project tapik, a type-safe DSL for defining HTTP APIs in Kotlin, became more than a library. It became an experiment in AI-augmented engineering.

• What changes when AI becomes your primary collaborator?
• Where does it accelerate you?
• Where does it confidently fail?
• What skills become more important?

Through concrete examples in Kotlin, I'll show how AI shifts the engineer's role from "code writer" to architect, reviewer, and decision-maker, and what that means for our profession moving forward.

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Talk 2: Type-safe tax calculations; Using Context Parameters
Pim van Gurp - Software Engineer @ Flock.

In this talk we’ll explore how two powerful Kotlin features (context parameters and Arrow's Raise DSL) combined to push time and error rules into the type system.

Context parameters allow us to change contextual input while keeping the call side consistent. This allows us to calculate income tax with X % in 2025 and Y % in 2026.

Furthermore, Arrow's Raise DSL gives us typed, structured error handling without exceptions, making every failure path explicit. Which enhances this typed domain even more.

No tax expertise required, just bring your joy for type systems.