Skills | Gerwin Kuijntjes

I’m a backend and infrastructure engineer who also builds products. Most of my work is in .NET (C#) for the backend, React or Astro for the frontend, and Kubernetes with OpenTofu for infrastructure. I look at both the technical architecture and the way people will use it. Right now my work is mostly internal tools, automation and AI integrations: connecting systems so data ends up where it belongs on its own, and removing work that used to be manual.

After working with several stacks, I’ve found that the difficult parts rarely change. API design, distributed systems, database performance and infrastructure costs do not depend much on a particular language or framework. That makes unfamiliar tools easier to pick up because I know what to look for and which questions to ask.

Outside my day job, I co-founded StaticForm, a form-backend SaaS that I built from scratch and brought to production. I maintain the product, backend, frontend, infrastructure and monitoring for real users. That experience has changed how I approach problems in existing codebases too.

My strongest areas are infrastructure and backend: production Kubernetes setups, infrastructure as code, cloud cost reduction and APIs that hold up in use. At a previous job, I moved the complete hosting stack from Azure App Services to a self-hosted K3S cluster. It still saves them more than €1,400 a month. I also convert server-side websites to static sites when that is a good fit because they are simpler, safer and faster.

Non-technical skills

Stakeholder communication: Primary point of contact for stakeholders: handling support questions and gathering requirements through intake conversations.

Technical writing: Writing documentation, architecture overviews, and decision documents that are accessible to non-technical readers as well.

Cost analysis: Making infrastructure costs transparent and building a business case for migrations or architecture changes.

Product ownership: Taking a product from idea to production, including prioritization, scope definition, and delivery.

Technical capabilities

Backend: Building APIs and backend services in .NET (C# / ASP.NET Core). REST APIs, authentication, database design, error handling. This is where most of my actual work time goes.

Infrastructure and DevOps: Setting up Kubernetes clusters, writing OpenTofu infrastructure as code, GitOps with ArgoCD, managing cloud costs. I prefer owning the infrastructure rather than renting managed services.

Frontend: Building SPAs with React (Vite) for SaaS products, and static sites with Astro for content-heavy websites. I’m not primarily a frontend engineer, but I can build complete products.

Database: PostgreSQL for most things. Query optimization, indexing, schema design.

AI & LLM: LLM integrations for classification, summarization and validation in production projects. I work daily with AI-assisted and agentic coding workflows, including prompt design, context management and cost control. Experience with Anthropic Claude and OpenAI.

Full Stack: I can take a product from idea to deployed infrastructure. StaticForm is a concrete example: a form-backend SaaS I co-built and co-own, with real paying users, submission queuing with retries, load balancing, spam filtering, full observability with action logging and failure alerts, multi-channel notifications, and a complete admin and subscriber interface. Slicekit is a production-grade .NET + React SaaS template I built and sell under a commercial license.