Introduction

Building a web application is only the first step. Ensuring that it remains available, responsive, and healthy in production is equally important. Modern applications often depend on databases, external APIs, message queues, caches, and other services. If one of these dependencies becomes unavailable, your application may stop functioning correctly.

ASP.NET Core Health Checks provide a standardized way to monitor the health of your application and its dependencies. They help administrators, monitoring tools, and orchestration platforms determine whether an application is running properly and ready to handle requests.

In this tutorial, you'll learn what health checks are, why they're important, how to implement them in ASP.NET Core, and best practices for building reliable applications.

What Are Health Checks?

A health check is an endpoint that reports the status of an application and its dependencies.

Instead of simply checking whether the application is running, health checks can verify the availability of critical components such as:

This information helps detect issues before they affect users.

Why Health Checks Matter

Health checks play an important role in modern application deployment.

Some key benefits include:

Platforms like Kubernetes, Azure App Service, and Docker use health check endpoints to determine whether an application is healthy enough to receive traffic.

Types of Health Checks

ASP.NET Core commonly supports three types of health checks.

Liveness Check

A liveness check verifies whether the application process is running.

If the application fails this check, the hosting platform may restart it automatically.

Readiness Check

A readiness check determines whether the application is ready to accept incoming requests.

For example, the application may still be starting while establishing database connections.

Dependency Check

Dependency checks verify external services such as:

Even if the application is running, failed dependencies can impact functionality.

Register Health Checks

Health checks are registered during application startup.

C#
var builder = WebApplication.CreateBuilder(args);

builder.Services.AddHealthChecks();

This enables the health check framework in your application.

Map the Health Check Endpoint

Next, expose a health endpoint.

C#
var app = builder.Build();

app.MapHealthChecks("/health");

app.Run();

When you browse to:

Code
/health

the application returns its health status.

This endpoint can be monitored by load balancers, monitoring tools, or cloud platforms.

Add a SQL Server Health Check

Most applications depend on a database.

Register a SQL Server health check.

C#
builder.Services.AddHealthChecks()
    .AddSqlServer(
        builder.Configuration.GetConnectionString("DefaultConnection"));

The endpoint now verifies that the database is reachable.

If the database becomes unavailable, the health status changes accordingly.

Monitor Redis

If your application uses Redis for caching, you can include it in your health checks.

C#
builder.Services.AddHealthChecks()
    .AddRedis(
        builder.Configuration.GetConnectionString("Redis"));

This confirms that the cache service is accessible.

Add a Custom Health Check

Sometimes you need to monitor application-specific logic.

Create a custom health check by implementing IHealthCheck.

C#
using Microsoft.Extensions.Diagnostics.HealthChecks;

public class StorageHealthCheck : IHealthCheck
{
    public Task<HealthCheckResult> CheckHealthAsync(
        HealthCheckContext context,
        CancellationToken cancellationToken = default)
    {
        return Task.FromResult(
            HealthCheckResult.Healthy("Storage is available."));
    }
}

Register the custom health check.

C#
builder.Services.AddHealthChecks()
    .AddCheck<StorageHealthCheck>("Storage");

This approach allows you to monitor any custom dependency or business-specific requirement.

Return Detailed Health Information

By default, the endpoint returns a simple status.

You can configure a custom response that includes additional details.

For example, a response may include:

These details make troubleshooting much easier when an issue occurs.

Health Check Status Values

Health checks typically return one of three states.

StatusMeaning
HealthyEverything is functioning normally.
DegradedThe application is running but has performance or dependency issues.
UnhealthyCritical components have failed and immediate attention is required.

Monitoring systems can use these states to trigger alerts or automated recovery actions.

Integrating with Kubernetes

Kubernetes uses health checks to manage containers.

Typical configuration includes:

These probes help Kubernetes determine:

Proper health checks improve application availability in containerized environments.

Monitoring Health Checks

Health endpoints are commonly integrated with monitoring platforms such as:

These tools continuously monitor application health and notify administrators when problems occur.

Best Practices

Follow these recommendations when implementing health checks:

Following these practices helps create reliable and maintainable monitoring solutions.

Common Mistakes to Avoid

Developers often make avoidable mistakes when implementing health checks.

Some common issues include:

Designing health checks carefully ensures they remain useful without affecting application performance.

Conclusion

ASP.NET Core Health Checks provide a simple yet powerful mechanism for monitoring the health of your application and its dependencies. By exposing standardized endpoints and verifying the availability of databases, caches, external services, and custom components, health checks help detect issues early and support automated recovery in modern deployment environments.

Whether you're deploying to Azure, Docker, or Kubernetes, implementing comprehensive health checks improves application reliability, simplifies monitoring, and reduces downtime. Incorporating health checks into every ASP.NET Core application is a best practice that contributes to more resilient and production-ready software.