As your applications grow, the performance and scalability of your Minimal APIs become crucial. In this post, I’ll walk you through how to scale your Minimal APIs in .NET 8, focusing on optimizing performance for high traffic environments.

Why Scaling Matters for Minimal APIs?

Minimal APIs are designed to be lightweight, but they still need to handle large volumes of traffic efficiently. A scalable API can manage increased demand without compromising performance or user experience.

1. Caching Responses to Reduce Server Load

Caching is an excellent way to reduce server load by storing frequently requested data in memory. You can use Response Caching to store API responses for a given period:

var builder = WebApplication.CreateBuilder(args);
builder.Services.AddResponseCaching();

var app = builder.Build();
app.UseResponseCaching();

app.MapGet("/data", () => {
    return Results.Json(new { message = "Cached Data" });
}).CacheOutput();

This ensures that repeated requests for the same data don't overwhelm your API.

2. Load Balancing Your Minimal APIs

Load balancing distributes incoming traffic across multiple instances of your API, improving both reliability and performance. If you’re hosting on Azure, configuring Azure Load Balancer with multiple instances of your Minimal API ensures better handling of traffic spikes.

• Step 1: Set up multiple instances of your API in Azure.
• Step 2: Configure Azure Load Balancer to route traffic efficiently between these instances.

3. Using Redis for Distributed Caching

For even better scalability, especially in distributed systems, you can use Redis to store cached data across multiple instances of your API:

builder.Services.AddStackExchangeRedisCache(options =>
{
    options.Configuration = "localhost:6379";
    options.InstanceName = "MinimalAPI_";
});

Now, cached data is shared across instances, ensuring consistency in your responses even when scaling horizontally.

4. Optimizing Middleware for Performance

Review your middleware pipeline and remove any unnecessary or redundant middleware components. For example, avoid serving static files or performing excessive logging in production environments:

app.Use(async (context, next) =>
{
    // Custom logic here, ensure it's optimized
    await next();
});

Also, use Asynchronous Programming wherever possible to avoid blocking the main thread:

app.MapGet("/async-data", async () => {
    await Task.Delay(1000); // Simulating async I/O
    return Results.Ok("Async Data");
});

5. Horizontal Scaling with Kubernetes

One of the most robust ways to scale your Minimal API is to deploy it in a Kubernetes cluster. Here’s a simplified outline:

• Step 1: Containerize your Minimal API using Docker.
• Step 2: Deploy your Docker image to a Kubernetes cluster.
• Step 3: Configure autoscaling rules using Horizontal Pod Autoscaler to automatically scale based on traffic.

kubectl autoscale deployment minimal-api --cpu-percent=50 --min=1 --max=10

This setup ensures that your Minimal API can scale horizontally, adding more pods as traffic increases.

Conclusion

Scaling your Minimal API in .NET 8 requires a combination of caching, load balancing, and containerization strategies. By incorporating techniques like response caching, Redis, and Kubernetes, you can ensure that your API can handle high traffic volumes efficiently without sacrificing performance.