Q&A

Building Secure and Scalable APIs in .NET 8

• By David Ramel
• 09/25/2024

APIs serve as the backbone of modern applications, enabling diverse systems to communicate and exchange data seamlessly. Whether you are building desktop apps, mobile apps, or SPAs for the web, nearly every application relies on robust back-end APIs to deliver business functionality.

However, as application demands increase and data sensitivity grows, ensuring that these APIs are secure, performant, and scalable becomes paramount. This is especially true in large-scale environments where a single vulnerability or performance bottleneck can have significant repercussions.

.NET 8 brings a host of new features and improvements designed to help developers create APIs that meet these high standards. From advanced authentication and authorization mechanisms to tools for optimizing performance under heavy loads, .NET 8 equips developers with the capabilities to build APIs that can handle the most demanding scenarios. But knowing what tools are available is just the first step. Implementing them effectively requires a deep understanding of best practices and potential pitfalls.

In the upcoming Live 360! tech event that encompasses several themed conferences for developers and IT pros, Tony Champion, president of Champion DS, will dive into those best practices and pitfalls in his session titled, "Building Secure and Scalable APIs in .NET 8." Drawing from his extensive experience in developing APIs for complex, data-sensitive environments, Tony will share insights on how to structure APIs for maintainability, implement multi-layered security measures, and ensure performance and scalability from development through deployment at the big November event in Orlando.

His presentation comes in the VSLive! developer conference hosted at the event, which also hosts conferences focused on data, AI, clouds & containers and more.

While going hands-on with the best practices for building APIs in .NET 8, attendees are promised to learn:

• How to structure and build APIs in .NET 8
• How to secure APIs using multiple authentication methods
• How to make your APIs scalable

We caught up with Tony to learn more about his 75-minute, intermediate-level, Nov. 21 session in a short Q&A.

VisualStudioMagazine: What inspired you to present a session on this topic?
Champion: Having experience building highly secured and scaled APIs for numerous clients, I've learned a great many lessons on building such APIs. I wanted to share those lessons with others to help promote solid practices when creating any API.

Can you provide an overview of the key features of .NET 8 that support building secure and scalable APIs?
.NET 8 ships with everything you need to build secure and scalable APIs.

From giving you access to the entire lifecycle of a request, the ability to configure and extend authentication and authorization, .NET 8 gives you the power to create APIs to meet even the most demanding needs.

What are some of the best practices for structuring APIs in .NET 8?
Structuring solid APIs in .NET 8 mostly comes down to using solid development practices. Breaking APIs up into small logical data-based or function-based constructs helps to keep APIs easy to maintain. Keeping a structured and consistent naming convention will help in maintainability as well as usability by the end users. Dependency injection, proper error handling, and logging are important for not only maintainability but for system integrity as well.

How do you implement multiple authentication methods to enhance API security?
.NET 8 provides an AuthenticationBuilder that allows you to create and register multiple authentication methods within your API. For example, you can handle JWT tokens from multiple issuers, provide cookie-based authentication, and create a custom authentication method all from a single API.

Can you discuss a couple security pitfalls to avoid when developing APIs?
The biggest pitfall to avoid is simply not adding any level of authentication to your APIs. Even something as simple as token-based authentication is very important. You might think that there is nothing sensitive about the data you are returning so there is no need. But let's say you have an API that returns a list of guitars. It's public information and nothing is secretive or in need of controlling access to. But your API is used by your product and others. If someone were to come along and start making a large volume of requests, it could impact multiple users. By implementing something as simple as token-based auth, you remove people who abuse the API (whether intentionally or not).

What techniques can be employed to ensure APIs remain performant under heavy load?
The absolute best way to ensure performance is by doing extensive load testing. You will often be surprised at where bottlenecks show up when your system is under heavy load. You might have a DB that is under too much strain that needs to be scaled or maybe a caching strategy needs to be developed. You might have an internal API that is called that is slow in its response. You might run into resource limits like trying to write too many blobs to a storage account. The time spent testing during development will be well worth the investment.

Once an API is deployed, auditing and monitoring its health is crucial. This can be done in a number of ways: logging and tracking events in something like Azure's Application Insights, monitoring response times of APIs, etc. By keeping track of performance, you can handle issues before they cause any major headaches.

How do you approach scalability in API design?
Designing scalable APIs is all about having a solid understanding of your data and the workflows needed to act on that data.

When it comes to data, the first step is having a good grasp on the size and structure of the data. The more data you receive or return in an API call, the heavier the load. It might seem helpful to return all of the data you have available for an object. But each piece of unnecessary data will have an impact. It might seem small when returning a handful of objects, but when you are returning hundreds or thousands, that extra data adds up.

The number of objects returned should be considered. It is common for developers to build APIs that return a small set of data during testing, but when those same APIs end up in production, the data sets grow significantly larger. Understanding the potential number of objects being returned will help you determine if paging should be added and when it should not. For instance, returning a list of states does not require any paging, but a list of all of the cities in the U.S. most likely should.

APIs should be fast and efficient. The best way to do that is for the API to only do the minimum that is required at that instance. If you have an API that has to perform a significant workload on a piece of data, it might be more efficient to offload that work to another process. An example would be for the API to add the data to a queue that can be processed internally with a different application. That way the API has a nice prompt return instead of having to wait until the process is complete. Having a solid understanding of the system workflows will help to determine how an API should be constructed.

Note: Those wishing to attend the conference can save hundreds of dollars by registering early, according to the event's pricing page. "Save $400 when you register by the Super Early Bird deadline of Sept. 27!" said the organizer of the event, which is presented by the parent company of Visual Studio Magazine.