invocation.io

Stripe Certified Professional Billing Architect

Payment systems that move millions. Platforms that don't break.

Andrej Dragojevic

I'm Andrej — an engineer with 12+ 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.

Start a projectSee the work

Trusted by

BabbelGigSocialeifasSponsoredPissup TourseSalon

12+

years shipping in production

Fintech, marketplaces, and SaaS — independent delivery since 2014.

50+

projects delivered

From two-week rescues to multi-year platform ownership.

$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.”
Tyler Thompson, CEO, GigSocial

01 / Services

Four ways I can help

Deep payments expertise, full-platform delivery, and senior judgment on tap — pick the engagement that fits.

Payment Integration & Migration

Integrations and zero-downtime migrations across Stripe, Adyen, and PayPal. I've moved hundreds of millions in recurring revenue for clients like Babbel.

  • Zero-downtime provider migrations
  • Subscription billing & dunning that recovers revenue
  • Cards, wallets, ACH, SEPA — every method your market needs
Learn more

Platform & MVP Development

Two-sided marketplaces, SaaS products, and MVPs built end to end — database schema to production deploy, with billing wired in from day one.

  • Marketplaces with escrow, wallets, and payouts
  • MVPs that validate fast without becoming throwaway code
  • SaaS scaling: multi-tenancy, billing, background jobs
Learn more

Technical Consulting & Fractional CTO

Architecture reviews, payment audits, team leadership, and project rescue. Senior judgment without the full-time hire.

  • Architecture & payment system audits
  • Fractional CTO for funded startups
  • Project rescue when delivery has stalled
Learn more

Automation & AI Systems

Automated workflows that hold up in production. I run my own automated delivery platform daily — this is how I work, not a side bet.

  • Content, outreach, and ops workflows that run on schedule with human sign-off
  • Back-office process automation with error handling and observability
  • LLM features built into your product, engineered like real systems
Learn more

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.

All case studies

Babbel

EdTech

Migrating millions in recurring revenue with zero downtime

Adyen → Stripe migration of Babbel's recurring billing — hundreds of millions in revenue, zero downtime.

$100M+recurring revenue migrated

Read the case study

GigSocial

Social Commerce

Building a complete influencer marketplace from scratch

Two-sided creator marketplace with escrow, wallets, and global payouts — zero to thousands of transactions monthly.

1000smonthly transactions

Read the case study

eifas Licensing GmbH

FinTech

Modernizing a legacy fintech platform without stopping it

Led the AngularJS → React modernization of a live accounting platform — 100% uptime throughout.

100%uptime during migration

Read the case study

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, delivered in one to two working days, findings you can act on.

See the reviews

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.

  1. 01

    Scope

    A call and a short written assessment: what you need, what it costs, where the risks live. No discovery theater.

  2. 02

    Plan

    Architecture, milestones, and a first deliverable inside the first two weeks. You see working software early.

  3. 03

    Ship

    Production-grade delivery with tests, monitoring, and honest weekly updates — accelerated by my automated tooling.

  4. 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

Founder, Sponsored · Co-founder, DigitalOcean

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

We went from idea to a fully working booking platform in record time. The team understood exactly what salon owners needed and delivered a product our customers love using every day.

Jovan Stefanovic

Partner, eSalon.rs

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.

Start a projectcontact@invocation.io

I reply within one business day. Currently booking for August 2026.