I build complex software for businesses that can't afford to get it wrong.

I'm Konstantin. Former product leader at N26 and Urban Sports Club. Payments. GDPR. Data isolation. Marketplace infrastructure. The stuff most developers avoid. You focus on your business. I'll build the infrastructure.

About

I don't just build products—I build them, ship them, and keep them running. Product thinking, technical execution, and operations, end to end.

At N26, I owned payments infrastructure for 3M+ users—incident response, PSD2 compliance, Apple Pay and Google Pay launches across Europe. Promoted four times in two years. At Urban Sports Club, I led payments, platform engineering, and site reliability: fraud detection (92% reduction, €2.2M saved), cloud migrations, legacy system upgrades, and the kind of debugging where money goes missing and someone has to find it.

Now I build custom platforms for businesses that need the whole thing—product strategy, architecture, implementation, monitoring, and ongoing operations. From concept to production in weeks, not months.

Recent work spans healthcare platforms, e-commerce infrastructure, and practitioner management systems. I'm selective about what I take on—I work on projects that empower people, in domains where getting it wrong has real consequences.

Recent Work

Kaufmann Health – Therapy Marketplace

A marketplace that connects people with body-oriented psychotherapists in Germany. Patients find the right therapist, book directly, and pay—all in one place. I built and run the entire platform solo: matching, scheduling, payments, acquisition, and operations.

Live and growing. Stack: Next.js, Supabase, Cal.com, Stripe, Resend.

Health Practitioner Digitization

Online course platform and digital infrastructure for an independent health practitioner, combining technical implementation with project management for clients who need both execution and guidance.

Work

Head of Academy

Jul 2023 - Nov 2024

Built and led a 12-month Product Management certification program from curriculum design to operations.
Recruited and managed 14 coaches and a Customer Success team, serving 150+ students across 10+ courses.

Lead Product Manager

May 2022 - Feb 2023

Built and launched an EDI integration (ISO standard) for supermarket-to-supplier order communication—hardcore B2B infrastructure with legacy system constraints.
Drove technical integration with enterprise partners while managing product roadmap, recruiting, and engineering team operations.

Lead Product Manager — Payments, Platform & Site Reliability

Apr 2020 - Apr 2022

Owned payments, partner payouts, finance, and compliance across two brands. Reduced payment-related fraud by over 92%, saving €2.2M annually.
Led the Platform tribe: migrated core infrastructure from AWS to Google Cloud, introduced microservices, and upgraded legacy frameworks (including a PHP version no longer receiving security updates) used by 6+ engineering teams.
Oversaw Site Reliability Engineering. When money was missing or transactions didn't reconcile, my team investigated and resolved it.

Co-Founder

Jun 2019 - Feb 2020

Built an ordering platform for restaurants sourcing from small-scale local suppliers. Global Top 25 in the Pioneer Tournament (Marc Andreessen, Patrick Collison, Stephen Wolfram).

Product Owner — Cards & Payments

Apr 2017 - Apr 2019

Promoted four times in two years—from Customer Service to Product Owner leading three payments teams and managing card infrastructure for 3M+ users.
Launched Apple Pay and Google Pay across 10+ European markets. Enabled UK and US expansion by making card processing multi-currency. Ensured PSD2 and GDPR compliance.
Managed major production incidents with direct customer impact. Grew team from 3 to 14. Worked directly with Google, Mastercard, and card processing partners.

Contact

Let's build your next product

If you need a custom product or digital infrastructure but don't have an in-house engineering team, choose how you'd like to start the conversation.

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Book discovery call

Ideal if you already have a project or idea and want to explore scope, timelines, and fit.

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