I build product and modernize the systems behind it
Independent software engineer. Available for freelance projects from November 2026.
I'm Elias, a senior software engineer with 15 years building web platforms for startups and scale-ups. Seven years at SumUp: first modernizing the platform, then leading teams across e-commerce, web, and quality. Full-stack with a frontend bias: TypeScript, Node, Go, React, Next.js, event-driven systems. I ship product, and I'm equally at home on the hard, unglamorous work: migrating a monolith, rebuilding a brittle CMS, getting a project back on track when it goes sideways. I care about keeping code review trustworthy as more of the codebase becomes AI-assisted, and I work agentically every day.
Services
How I can help
Focused engineering work, scoped to what your team actually needs right now.
Build
Ship product. From first release to something that scales.
- Full-stack delivery in TypeScript, Node, Go, React and Next.js
- New products and features from zero to production, with a clear definition of shipped
- Event-driven services and API design that hold up as the product grows
- Extra capacity for a team that has more roadmap than people
Let's talk about what you need shipped and by when.
Book a call →Modernize
The turnaround work. I untangle what is slowing your team down.
- Legacy migration: monolith to modular or event-driven
- Rebuilding systems nobody wants to touch
- Performance, stability, and developer velocity
- CMS and platform consolidation
Let's discuss what's brittle, slow, or blocking your roadmap.
Book a call →Strengthen
Quality and AI workflows. Plus leadership, when the problem is bigger than the code.
- Agentic development: adoption, guardrails, review at scale
- Technical and team health audits
- Fractional EM or advisory when the challenge is organizational
Let's shape the right format together.
Book a call →Curriculum Vitae
Experience & Background
A mix of hands-on engineering, leadership, and product thinking.
Independent Software Engineer
- Freelance and contract engineering for startups and scale-ups.
- Focus: platform modernization, event-driven systems, API-first design, full-stack product delivery.
- Stack: TypeScript, Node.js, Go, React, Next.js, Kafka, Kubernetes.
Engineering Manager · Purchase & Logistics, Website Journey and Quality at SumUp
- Led the replatform of the global marketing website to Builder.io on React and Next.js/Node.js, rolled out across 35+ countries and enabling autonomous publishing for marketing teams.
- Built a central quality function and CI practices that reduced production regressions and made release timing predictable.
- Designed and delivered checkout and payment improvements that reduced friction in the purchase flow and lifted conversion.
- Introduced agentic developer workflows (Cursor) into delivery while keeping code review discipline and quality standards intact.
- Owned architecture and technical direction across Purchase, Website Journey and Quality.
- Led three cross-functional teams with 11 full-stack engineers, covering hiring, delivery planning and stakeholder alignment.
Engineering Manager · Ecom Platform at SumUp
- Led the migration from a legacy Ruby monolith to an event-driven modular architecture in Go and TypeScript, rolled out across 35+ countries.
- Owned the global e-commerce platform stack and the operational runbook for purchase flows.
- Introduced DORA metrics across the department to make delivery performance visible and guide continuous improvement.
- Managed 5+ full-stack engineers in the stream-aligned Purchase domain, owning delivery and operational reliability for card-reader purchases.
- Merged two teams into a unified Purchase team during a departmental reorganization, clarifying service boundaries and delivery flow.
Senior Software Engineer · Ecom Platform at SumUp
- Migrated monolithic services to a modular Go-based platform, improving deployability and service boundaries.
- Led system design for new services and mentored engineers through the transition.
Senior Software Engineer · Consideration at SumUp
- Rebuilt website content systems and a reusable component library in React and Next.js.
- Improved page performance and gave marketing teams autonomy to publish without engineering support.
Software Engineer at ZenGuard GmbH
Full-stack development on ZenMate consumer products and web properties.
Software Engineer at Coureon Logistics
- Built customer-facing front-end applications and a plugin integrating Coureon with a third-party e-commerce system.
- Developed the initial MVP of a warehouse management application.
Co-Founder at betweeen.com
- Co-founded betweeen.com, a platform for improving company communication through personality traits.
- Took the product from MVP to a working product with a small bootstrapped team, covering engineering, product and ideation.
Freelance Web Developer at EK Design & IT
- Freelance full-stack web development for clients of varying size, delivering websites and internal company tooling.
- Built the front-end application for soundfluence.com, a platform connecting musicians internationally.
Education
B.Sc. Computer Science (International Media & Computing)
HTW Berlin · 2013 – 2017
Qualified IT Specialist, System Integration
ITERGO Munich / SPE Siemens · 2007 – 2010
Core Competencies
- Engineering: full-stack delivery, event-driven architecture, system design
- Tech: TypeScript, Node.js, Go, React, Next.js
- Infra: Kubernetes, Kafka, RabbitMQ
- AI-assisted development: agentic workflows, AI in code review and CI/CD
- Leadership: team coaching, hiring, quality culture
Let's get in touch
Building something new, adding capacity to your team, or stuck on a migration you keep postponing? I'm happy to take a look.