Welcome to my professional portfolio! With years of experience in software development, data-intensive backend solutions, IoT platforms, and GIS applications, I enjoy building innovative, scalable, and efficient systems that solve real-world challenges. Here's an overview of my expertise and key projects.

• Software Development: Focussed on development of backend services with experience in multiple frontend technologies.
• Cloud Computing: Build Azure infrastructures with various technologies.
• CI/CD: Set up pipelines, deploy with Infrastructure as Code.
• Data Analytics: Timeseries ingestion, anomaly detection, machine learning and third party software integration.
• Technologies: C#, .NET, Terraform, Azure with numberous services, Databases (such as PostgreSQL and SqlServer), Kubernetes, Docker
• Domains: Energy, EV Charging, Urban Water, Geo Science, (Geo)Hydrology, Hydraulic and Climate Modeling.

Client: Alfen
Goal: Scalable backend for managing 10,000+ EV charging stations via OCPP.
Highlights:

• Developed infrastructure-as-code with Azure and Terraform.
• Created API endpoints and a proof-of-ownership flow in TypeScript.
• Designed a gateway for managing WebSocket connections and resource-intensive requests.
• Technologies: .NET, C#, Azure Functions, Service Bus, Kafka, Docker, PostgreSQL, React Native.

Client: Dutch Municipalities
Goal: SaaS platform for managing climate adaptation grants.
Highlights:

• Designed authentication and role-based access control.
• Automated deployments and CI/CD using Terraform and GitHub Actions.
• Built scalable APIs and a TypeScript client for integration.
• Technologies: .NET, C#, Azure Functions, CosmosDB, Terraform, React, TypeScript.

Client: HaskoningDHV
Goal: IoT platform for anomaly detection in water systems.
Highlights:

• Scaled from software engineer to architect, leading a team of 20 developers.
• Integrated machine learning for sensor quality labeling and predictive analytics.
• Led third-party integration with Tableau, Grafana, and PowerBI.
• Technologies: .NET, C#, Azure Data Explorer, Azure Service Bus, SignalR, Angular, Docker, CosmosDB.

Client: HaskoningDHV & Achmea
Goal: Sensitivity analysis of rainfall impact on 2M+ Dutch properties.
Highlights:

• Hydraulic modeling for over 1,000 cities.
• Developed a UI portal for public and governmental use.
• Technologies: Python, Rasterio, PostgreSQL, Azure.

Client: Various Municipalities & Knowledge Institutes
Projects:

• Catch Tool: Web app for sustainable water management.
  • Technologies: Python, Django, Angular, Wagtail.
• Nereda Design Tool: Wastewater treatment plant parametric design.
  • Technologies: Parapy, React, Docker, Kubernetes, Hydraulic Modelling.

• Portfolio: Nautilus IT
• LinkedIn: linkedin.com/in/jonnekleijer
• Email: [email protected]

Feel free to explore my projects and connect with me for collaborations!