I’m currently working on several cloud-native projects hosted on Google Cloud Platform (GCP) that use .NET for the API and React for the UI. These projects rely on GCP’s Identity-Aware Proxy (IAP) to handle authentication, which occurs before any requests reach the Application Load Balancer or the application itself.

While GCP’s IAP offers robust security benefits, configuring a .NET and React application to work seamlessly with it—both locally during development and when deployed to a Cloud Run instance as a Docker container—proved to be more challenging than I expected. The available documentation and resources for this setup are sparse and often fragmented, making it difficult to piece together a clear solution.

This blog post is my way of sharing the lessons I’ve learned along the way. By outlining the steps and solutions that worked for me, I hope to save others from the trial and error I experienced and provide a clearer path for integrating GCP IAP with .NET and React applications.