European startup founder noticed my contribution and asked for a call. What should I be ready for?

I’m a 3rd year CS student and something unexpected happened recently.

I’ve been contributing to a small open-source project for learning purposes. Nothing huge mostly fixing small issues, understanding the codebase, and trying to learn how real production systems work.

A few days ago, the founder of the company (they’re based in Europe) reached out to me and asked if we could have a call. From the conversation so far it sounds like he wants to know more about my background and possibly see if I could fit into some role on the team.

The thing is… I’m honestly still a beginner and I don’t have any real industry experience yet. I’m still in university and most of my experience comes from personal projects and trying to understand real-world codebases.

Some of the things I’ve built / worked on recently:

• A few full-stack web projects
• Contributed to an open source project (the one where he found me)
• Built small tools to learn APIs, authentication, SaaS style systems
• Experimented with things like cron jobs, email notifications, payment gateways, etc. mostly just to understand how real products work internally

But I’ve never actually worked in a startup or production environment before.

From what I understand, this call will mostly be about:

• my background
• how I think about building things
• and whether I could fit into their team

So I wanted to ask people who have more experience with startup interviews:

What kind of questions do founders usually ask in situations like this?

Especially when:

• you’re still a student
• you found them through open source contributions
• and you don’t have formal work experience yet

Also:

• What things should I prepare beforehand?
• What signals do founders usually look for in early engineers?
• Are there specific technical topics or system concepts I should revise?

Any advice would really help. I’m excited but also slightly nervous since this is my first time talking to a startup founder about something like this.

Thanks 🙏