Exposing .NET Core Web API on IIS on EC2 instance

You want to expose your web API to the Internet so that users can call that API. In your setup, you have a web server (IIS) running on an EC2 instance and listening for incoming requests.

Please refer to this knowledge center article that explains how to allow inbound traffic on port 80 and/or 443 for an EC2 instance. It is recommended to only allow traffic for HTTPS (port 433) because it is more secure.

If you want to understand in detail how the Security Groups described in that article work, please refer to the Virtual Private Cloud documentation.

Note that you do not necessary need an EC2 instance for hosting a web API implemented using the .NET platform. Depending on your requirements, you might want to consider to host your application on AWS Lambda. In this blog post, you can read about the differences and advantages of both approaches.

Another option for hosting a web API is containerizing your application and using a container orchestration framework for running it. Here, Linux-based containers offer more advantages than Windows-based containers. Since you build your application on .NET Core which supports cross-platform targets, you might want to consider using Linux as your platform. AWS offers multiple ways to run containerized applications. In this blog post, you can read about running a .NET based web API using AWS App Runner. If you want to use Kubernetes, there is also a way for that - using Amazon EKS. Another (easier) option is to use Amazon ECS and AWS Fargate - you can read this blog post for details and advantages of this approach.

Now you can make an informed decision what option fits your requirements - a classic server-based model, a modern container app, or even a serverless architecture.