Stripe Certified Professional Billing Architect
I build the platforms money runs through.
Two-sided marketplaces, digital wallets, escrow, payouts, subscription billing, internal accounting tools — designed and built from scratch, fixed scope, handed over. When the system already exists, I migrate it between providers or audit it. I'm Andrej: ten-plus years of this for companies like Babbel and GigSocial, hands-on from the ledger schema to the deploy.
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+
in recurring revenue migrated
Babbel's Adyen to Stripe migration, 2024–2026 — cards, wallets, PayPal and SEPA, zero customer-visible downtime.
0
downtime across migrations and live rebuilds
Babbel's provider cutover, eifas's platform modernization, ArenaMaster's rebuild — 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 / What I build
Money is the part of a platform you can't get wrong twice
Ledgers, escrow, payouts, subscription billing, provider migrations — the systems where a bug is a liability. I build them from scratch for founders and companies who want one senior engineer making the calls, and I fix or move the ones that already exist.
Every way in, priced
Audit → migrate → build → lead
Fixed scope with a number attached, at every rung. Start with the audit if you're not sure what you need; its fee comes off whatever you book next.
Who this works for
Founders and operators who want things done, not managed.
You know what you want built and don't want to project-manage getting there. You get one senior engineer who makes the calls, tells you when something is a bad idea, and ships — not a team you have to coordinate, not a status meeting you have to run, not a change request for every decision.
If you'd rather approve outcomes than steps, you'll like working this way. If you want to be in every decision, an agency is a better fit, and I'll say so on the first call.
How a one-person practice ships at team pace. One senior lead, a vetted network when scope needs design or mobile, EU/US hours. I run an agent fleet for the mechanical work behind the same review gates I use on my own production systems; the judgment is mine.
02 / Selected work
Real projects, measurable results
A marketplace built from an empty repository and still running years later. $100M+ in recurring revenue moved between providers with zero downtime. A live fintech platform rebuilt without stopping it.
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: Marketplace payouts, FBO accounts and tax forms, wallets and ledgers that survive, 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.