Specialist .NET Developer | AI & Identity

Sound familiar?

Your board is asking about the AI strategy. Your team built a POC, but it only runs locally. The step to production turns out to be bigger than expected.

Meanwhile, your enterprise prospect is asking when SSO will be ready. Your competitor already has it. And every week of delay costs you momentum.

You're not looking for extra hands. You're looking for someone who's solved this before.

Schedule an introduction

I'm Chaïm Zonnenberg. 20+ years in .NET, 2x cum laude university degree, Microsoft Certified Identity & Access Associate, 4 SSO implementations at organisations like ABN AMRO. I've built and launched 2 SaaS products myself (135+ customers) — I know the challenges of product development from the inside. As an embedded specialist I work 2 days a week with your team, typically 3–6+ months.

More about me

EXPERTISE

Where I make the difference

I focus on the technical challenges where internal teams often lack the time or specific expertise.

AI Integration

Your customers expect AI features in your product. Your team wants to build, but nobody has shipped it to production before. I ship working AI features in your SaaS — from prototype to production, including monitoring and responsible deployment under the AI Act.

Identity & SSO

Your enterprise client demands SSO. The deal is under pressure. I build enterprise-grade authentication, so that deal no longer falls through on SSO and your client gains confidence.

AI-powered Engineering

Your backlog is growing faster than your team can keep up. I deliver complex .NET features with AI tooling in a fraction of the lead time. But more importantly: I help your team make the shift to AI-first development. From resistance to productivity — with Claude Code and GitHub Copilot, so your velocity goes up permanently.

Technologies I work with

.NET C# Azure SQL Server OpenID Connect Entra ID Claude Code OpenAI Semantic Kernel

Schedule an introduction

How we work together

From problem to working solution in three steps

Introduction

A 30-minute call. I listen, ask questions, and give you an honest assessment: whether I'm the right fit and how I'd approach it.

Fast onboarding & first result

I dive into your codebase and deliver a concrete result within the first week. No months of onboarding. At ABN AMRO I was productive within days.

Push through

I work as an embedded specialist: 2 days a week, multiple months. Those complex features your team kept postponing? I push through. Architecture, code and knowledge transfer — so your team can carry it forward.

Experience & references

20+ years at ABN AMRO, PGGM, Van Lanschot & more · 2x cum laude university · Microsoft Certified Identity & Access

Complex migration project delivered successfully

"Chaïm managed a large and complex migration project for us and brought it to a successful conclusion. He got up to speed exceptionally fast and consistently made the right decisions based on his deep knowledge of .NET and SQL Server."

Cees

Software Architect at multinational

Proactive from day one

"Chaïm is a true professional. One you don't want to let go from day one. Proactive is his motto. He picks up what matters and doesn't let go until it's resolved."

Robert

IT Team Lead at financial institution

Advised the board on architecture

"Chaïm filled the advisory role of Software Architect at our organization. He advised the board and gave direction to the software architecture. He also guided the development team into the world of microservices and brought knowledge about Microsoft Azure."

Chantal

IT Operations Director