Stripe Certified Professional Billing Architect
Payment systems that move millions. Platforms that don't break.
I'm Andrej — an engineer with 10+ years shipping payment infrastructure, marketplaces, and platforms for companies like Babbel and GigSocial. Hands-on from database schema to deploy, alone or with my delivery network.
Trusted by
BabbelGigSocialeifasSponsoredPissup Tours
10+
years shipping in production
Fintech, marketplaces, and SaaS — independent delivery since 2015.
2.4M+
downloads on a product I run
The ArenaMaster companion addon — built, shipped, and operated solo.
$100M+
moved for clients
Recurring revenue migrated, marketplace transactions processed, and payouts delivered worldwide.
0
downtime across provider migrations
Babbel, eifas, and every cutover since — customers never noticed a thing.
“They built our entire marketplace from scratch — escrow payments, seller payouts, the whole thing. Three years later, we're still working together.”
01 / Services
Four ways I can help
Deep payments expertise, full-platform delivery, and senior judgment on tap — pick the engagement that fits.
Every engagement is AI-accelerated. I run Antrix OS — my own automated development platform — so you get senior judgment at multiple-engineer throughput, without a team-sized invoice.
02 / Selected work
Real projects, measurable results
From payment migrations moving hundreds of millions in revenue to marketplaces paying out sellers worldwide.
Fixed-fee code reviews
Someone else built your codebase? Find out what you actually have.
Independent reviews of agency-built and AI-built codebases. Fixed fee, from a 90-minute diagnosis to a two-week deep dive, findings you can act on.
From the field: Adyen to Stripe — the complete migration guide and more in Guides.
03 / How I work
A process built on not surprising you
I work as a partner, not a vendor — and partnership runs on predictability. Here's exactly what happens after you reach out.
01
Scope
A call and a short written assessment: what you need, what it costs, where the risks live. No discovery theater.
02
Plan
Architecture, milestones, and a first deliverable inside the first two weeks. You see working software early.
03
Ship
Production-grade delivery with tests, monitoring, and honest weekly updates — accelerated by my automated tooling.
04
Operate
I stay accountable after launch. Most clients keep working with me for years, not weeks.
04 / Clients
What it's like to work with me
They built our entire marketplace from scratch — escrow payments, seller payouts, the whole thing. Three years later, we're still working together and the platform handles thousands of transactions monthly.
Tyler Thompson
CEO, GigSocial
Andrej and team did a fantastic job building a production grade application for our SaaS business.
Mitch Wainer
Co-founder, DigitalOcean · Founder, Sponsored
Andrej is talented, easy to work with, challenges your ideas where needed, and keeps deadlines.
Mads Thorsdal
Founder, Awesome Adventures Group
The cooperation with Andrej and the team was always characterized by the highest professionalism.
Matthias Nebur
Product Manager, eifas GmbH
The team understood exactly what salon owners needed and delivered a product our customers love using every day.
Jovan Stefanovic
Salon owner, eSalon customer
Have a payments problem? Something broken in your platform?
Tell me where it hurts. I'll tell you honestly whether I can help, what it takes, and what it costs.
I reply within one business day. Now booking new engagements.