About

Hi, I'm Felix Seip

I'm a freelance product engineer based in Frankfurt — full-stack across backend, frontend, and mobile, with Java, Spring Boot, and cloud architecture as my deepest specialty. Across more than ten years in software engineering I've helped product teams, startups, and dev studios cut complexity, de-risk delivery, and scale without rewriting everything a year later.

I bring hands-on development, commercial awareness, and architectural thinking to the same conversation — bridging the gap between what the business wants and what the software actually does. Modernising legacy systems, building data pipelines, standing up new backend services on AWS: the goal is always something lean, maintainable, and matched to the business behind it.

Who I work with

I support fast-moving teams that prefer long-term clarity to short-term hacks:

  • SaaS providers automating internal workflows
  • Product teams launching new customer-facing services
  • Engineering leads who need expert reinforcement on backend and cloud projects
  • Boutique dev and MVP agencies covering overflow work or a gap between hires

What I bring

I've delivered projects for companies including TUI, Micromerce, ING, BMW, and DB InfraGO, across tourism, B2B e-commerce, enterprise automation, and rail infrastructure. That work has looked like:

  • Breaking monoliths into resilient microservices
  • Building ETL pipelines and data processing workflows
  • Implementing LLM-powered support tools with RAG pipelines
  • Coaching developers in Clean Code, TDD, and system design
  • Designing, building, and marketing three of my own products — 23Brain, Smaipa, and Chips Story — from first commit to the App Store

Day to day that means modern Java, Spring Boot, AWS (Lambda, ECS, SQS/SNS, CDK), and integration work across systems like Salesforce, SAP, and Google DocumentAI.

How I work

I don't just write code. I work with you to understand the product, the team, and the constraints — so we can pick the technical path that survives contact with reality.

  • Structure without red tape: lean, clear, and focused on outcomes
  • Strong ownership: independent work, seamless in remote teams
  • Clear communication: technical depth that translates to stakeholders

Outside the code

I'm based in Frankfurt and work remote-first by choice rather than by default — I spent a year testing the other way, a new city roughly every month, and found it left me scattered and permanently half-settled. Staying in one place turned out to be the thing that gave me focus. When I'm not building something you'll find me climbing, sailing, or at a meetup arguing about AI, developer tooling, and product strategy.

Let's work together

Tell me what you're building and where it's getting stuck.

Get in touch