Open to freelance opportunities

Hi, I'm

Martijn
van Kreij

Senior Software Engineer·Cloud Engineer·.NET & Azure

Building robust, cloud-native solutions that scale and deliver real value. Focused on platform engineering, .NET backends, and Azure infrastructure.

10+
Years experience
5+
Years Azure
AZ-204
Certified
Azure Certified
.NET Expert
AI Explorer

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Azure Developer Associate
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Building software that actually matters

“With an eye for the latest trends and a passion for innovation, I always strive to build products that are not only great to make, but especially add value to the client.”

I'm a Senior Software Engineer with a decade of experience across a range of organisations — from government to finance. I've built and delivered valuable products that stand the test of time.

My focus isn't just on what's technically challenging — it's on building the right solutions that genuinely match client needs. With short communication lines, the right people at the table, and a critical eye on process and goal, I deliver solid, future-proof software.

  • Platform Engineering & Internal Developer Platforms
  • Azure Cloud Architecture & Infrastructure as Code
  • .NET Backend Development (C#, microservices, APIs)
  • CI/CD Pipeline Design & DevOps Culture
  • Tech Lead — architecture, mentoring, stakeholder alignment
  • Currently deepening expertise in Azure AI & Machine Learning
10+
Years of experience
5+
Azure cloud years
AZ-204
Azure certified
AI-102
Azure AI (pending)
Microsoft Certified
Gold Partner ecosystem
AZ-204Azure Developer Associate
Active
AI-102Azure AI Engineer Associate
Pending
AWS CCPAWS Cloud Practitioner
Active
📍
Oss, Netherlands
Remote-friendly & on-site
Available

Technologies I work with

Focused on the Microsoft Azure ecosystem, .NET engineering, and cloud-native infrastructure. Always exploring what's next.

Backend
C#
.NET
TypeScript
Cloud
Azure
API Management
Azure DevOps
Infrastructure
Pulumi
Bicep / ARM
Docker
Databases
SQL Server
Cosmos DB
Frontend
Angular
DevOps
PowerShell
Git
AIExploring
Azure AI

ALSO EXPERIENCED WITH

Azure Key VaultService BusLogic AppsApp ServicesAzure FunctionsCosmos DBAzure NetworkingVNetsPrivate EndpointsExpressRouteAzure Front DoorMicroservicesREST APIsOpenAPI 3YAML PipelinesARM TemplatesCI/CDScrumTech Lead

Where I've worked

Over 10 years delivering at organisations ranging from financial institutions to government — always via Rubicon Consulting & Technology.

Software Engineer — Simplify / IDP

Current
Rabobank·via Rubicon
Jan 2025 – Present

Leading the technical design and build of 'Simplify' — an Internal Developer Platform using a hub-spoke model to standardize networking, security, and data exchange across Rabobank's Analytics Platform. Selected and advocated Pulumi as the IaC and IDP technology.

  • Designed the IDP architecture together with architects, business, and engineers
  • Built a proof-of-concept provisioning Simplify's network design using Pulumi
  • Developed reusable IaC components for capability teams
  • Led workshops and technical sessions with all stakeholders
.NETPulumiIaCAzurePlatform Engineering

Software Engineer — Contextual Insights

Rabobank·via Rubicon
Apr 2024 – Dec 2024

Built the Contextual Insights platform — a widget-based data visualization solution integrated into Rabobank's internal applications. Delivered both .NET backend and Angular frontend features, and contributed to the developer journey for widget development.

  • Implemented Web Components, import maps, and modular widget loading
  • Developed a CLI tool to bootstrap new widgets
  • Built multi-project support and custom authentication features
  • Laid the foundation for a low-code journey for BI developers
.NETAngularTypeScriptWeb ComponentsSQLNPM

Cloud Engineer — BI App Platform

Rabobank·via Rubicon
Jun 2023 – Apr 2024

Migrated four BI applications from on-premise to Azure within six months, building and extending the BI App Platform to ensure compliance, governance, and zero-downtime migration.

  • Delivered all 4 apps on time, fully compliant with Rabobank governance
  • One application now serves 5,000+ daily users
  • Integrated ExpressRoute, Azure Front Door, and certificate management
  • Led IaC standardization using Bicep templates
Azure DevOpsBicepYAML PipelinesFront DoorNetworking

Cloud Engineer & Tech Lead — DEX Platform

Ministry of Foreign Affairs·via Rubicon
Sep 2020 – Jun 2023

Joined as Cloud Engineer on the Data Exchange (DEX) platform — a highly secured integration hub enabling Dutch embassies to exchange visa application data with European systems. Promoted to Tech Lead after two years.

  • Built and maintained secure APIs in Azure API Management
  • Developed connectors to external government systems (EUVIS)
  • Designed Azure networking: VNets, subnets, NSGs, private endpoints, Application Gateway
  • As Tech Lead: backlog ownership, architecture decisions, stakeholder collaboration
C#Logic AppsAPI ManagementAzure NetworkingBicepCI/CD

Cloud Engineer (.NET & Azure)

RNHB·via Rubicon
Apr 2020 – Jun 2020

Contributed to RNHB 2.0, extending .NET Core microservices and integrating Azure components to automate the mortgage application process.

  • Extended .NET Core microservices with new features
  • Integrated services via Azure Service Bus and API Management
  • Secured services with JWT tokens and Azure AD
C#.NET CoreAPI ManagementService BusCosmos DB
Earlier experience includes roles at Fourtress (Embedded/IoT), Bloomlife Inc. (Medical CI/CD), NXP Semiconductors (Autonomous driving R&D), and InfoBridge (.NET/CRM) — 2014 to 2020.

Featured work

A selection of impactful projects delivered at enterprise clients. Each project solved a real business problem with a solid technical foundation.

Discuss your project
Platform Engineering

Simplify — Internal Developer Platform

Rabobank·2025

Designed and built an Internal Developer Platform using a hub-spoke model, enabling teams across Rabobank's Analytics Platform to self-serve infrastructure deployments. Led the adoption of Pulumi as the standard IaC tool.

Impact:Adopted as standard tool across all capability teams
.NETPulumiAzureIaCHub-Spoke
Cloud Architecture

DEX — Data Exchange Platform

Ministry of Foreign Affairs·2020 – 2023

Built a highly secured API integration platform enabling Dutch embassies worldwide to exchange visa application data with the European Visa Information System (EUVIS). Evolved from Cloud Engineer to Tech Lead.

Impact:Powers visa processing for all Dutch embassies
C#Logic AppsAPI ManagementAzure NetworkingBicep
Full Stack

Contextual Insights — Widget Platform

Rabobank·2024

Developed a platform offering customizable, contextual data visualizations in widget form, integrable in any internal Rabobank application. Implemented cutting-edge frontend techniques for modular widget loading.

Impact:Enabled developer-led widget ecosystem
.NETAngularTypeScriptWeb ComponentsImport Maps
Cloud Migration

BI App Platform — Cloud Migration

Rabobank·2023 – 2024

Migrated four BI applications from on-premise to Azure within six months using a shared BI App Platform. Ensured full governance compliance, zero downtime, and standardised infrastructure for future migrations.

Impact:One app now serving 5,000+ daily users
Azure DevOpsBicepYAML PipelinesExpressRouteFront Door

Working on something interesting? Let's talk about your project.

Let's work together

Looking for a Senior Software or Cloud Engineer to join your team or take on a project? I'm available for freelance assignments. Let's discuss what I can build for you.

🏗️

Platform Engineering

Design and build Internal Developer Platforms, IaC frameworks, and cloud-native infrastructure on Azure.

☁️

Cloud Architecture

Architect secure, scalable Azure solutions — networking, APIs, serverless, microservices.

🔧

.NET Development

Full backend development: REST APIs, microservices, integrations, and cloud-native .NET applications.

🚀

DevOps & CI/CD

Pipeline design, IaC with Bicep or Pulumi, Azure DevOps best practices, and release automation.

Ready to start a project?

Whether you need cloud architecture, .NET development, or platform engineering — reach out and let's see how I can help.

Available for new projects📍 Oss, Netherlands🌍 Remote-friendly