Antonios Kioksoglou

Once a developer, now a professional maker. I’m CTO and co-founder of Zalster, I grew up in Gothenburg, and I support BK Häcken with more optimism than any dataset would recommend.

A website about me and my friends#

I built my first website when I was 12. It was about me and my friends, which made us the subject, the audience and the entire analytics department. It had no business model, no roadmap and no reason to exist. I have been chasing that feeling ever since: you make a thing, you put it online, and suddenly it is real.

The marketing accident#

Gothenburg is home. I studied computer science at Chalmers. Before Zalster I was a software engineer at Ericsson, on an in-house logging tag system written in Angular, Python and Erlang, which is a sentence that impresses exactly the right people. Then came Let’s Deal, where I built the website, frontend, backend and database. That is also where my career took a turn I had not planned: somebody had to do a lot of marketing automation, and that somebody was me.

It turns out marketing is an engineering problem in a nicer shirt. Events, data, feedback loops, and things that break quietly at 3 a.m. I have been hooked ever since. Meta eventually gave me five developer certifications, which is the closest an API has ever come to saying thank you.

Zalster#

In 2016 I built a SaaS for optimizing Facebook ads: budgets, bids and creatives, using a Bayesian algorithm and regression analysis. That SaaS is Zalster, which I co-founded and where I am CTO.

In 2016 this was futuristic. Today the ad platforms have their own versions, and any chatbot will explain the math over breakfast. That is what happens to futuristic things. Building it was a lot of fun, and that part has aged perfectly.

Then the robots showed up#

When GPT-3.5 arrived I fell for the hype, like half the internet. I started small: one function, one regex, one “why does this not work”. It was confident, tireless and wrong just often enough to keep me honest, like a junior developer with infinite energy and no fear.

The models got better. I got braver. Today I leave all of the coding to AI, with control. “With control” is doing a lot of work in that sentence, so here is what it means:

• Spec first. Agents work from a written brief, not a vibe. Vibes are for match days.
• Every diff is read. Money, permissions and data changes get read twice, and the boring ones get read too, because that is where bugs hide.
• Read-only by default. Agents don’t write to live data. Writes go through a reviewed path.
• Tests and evals gate changes. If it can’t be checked, it doesn’t ship. A red build does not get to kick off.

What I build now#

Professional maker sounds like a job title someone made up. Fair. It is also accurate: I work as an AI engineer and full-stack developer, building SaaS products, internal tools, e-commerce sites, plugins and AI agents with Claude Code and a small set of narrow sub-agents. I also work as a marketing technologist and marketing analyst for e-commerce brands: paid media on Meta, server-side tracking, attribution, data analysis and lifecycle automation.

If you want the practical version, the software, e-commerce and marketing pages show what that looks like, the articles go deeper, and the questions and answers are the short version.

Football, and BK Häcken in particular#

I love football, and I love BK Häcken, and those two sentences cover most of my emotional range.

BK stands for Bollklubben, “the ball club”, which is the most honest name in Swedish football. Yellow and black, from Hisingen, and worth every minute of stress.

I know the theory. Small samples lie. Goals are noisy. One match proves almost nothing, and every hot streak regresses to the mean eventually. Expected goals is a great statistic, mostly because it admits it is a guess. I can build a model that tells me to stay calm. Then the whistle goes, my priors leave the building, and what is left is a supporter with a posterior of “we win”.

Football is also the best product I know. The rules fit on one page, it ships every week, nobody reads the changelog and the hotfixes happen at half-time. VAR is code review for referees: slow, thorough and guaranteed to start an argument.

I am not neutral, and I am not trying to be. If you support another club, that is fine. I will just bring statistics.

The short version#

$ cat antonios.txt
name    Antonios Kioksoglou
home    Gothenburg
first   a website, age 12
school  Chalmers, computer science
2013    Ericsson, engineer
2014    Let's Deal, full stack
2016    Zalster, CTO + co-founder
speaks  Swedish, English, Greek
club    BK Häcken, lifetime deal

Get in touch#

The best way to reach me is by email. Tell me what you’re building, and I’ll tell you honestly whether I’m the right person. Mentioning Häcken is optional, but it will shorten the reply.

The facts in one place: the candidate summary.