Azure Functions in a cloud-first C# architecture

Azure Functions is a strong fit for event-driven workloads, background processing, webhook handlers, and bursty traffic.

When to use it

• You need automatic scale based on events.
• You want to run small focused units of business logic.
• You want to avoid managing server infrastructure for integration workloads.

Architecture guidance

Use Functions as orchestrators and adapters, not as monoliths. Keep core business rules in reusable service classes so the same logic can run in APIs, workers, and tests.

C# example

using Microsoft.Azure.Functions.Worker;
using Microsoft.Azure.Functions.Worker.Http;
using Microsoft.Extensions.Logging;
using System.Net;

public sealed class HealthFunction
{
    private readonly ILogger<HealthFunction> _logger;

    public HealthFunction(ILogger<HealthFunction> logger)
    {
        _logger = logger;
    }

    [Function("health")]
    public HttpResponseData Run(
        [HttpTrigger(AuthorizationLevel.Anonymous, "get", Route = "health")] HttpRequestData req)
    {
        _logger.LogInformation("Health endpoint called.");
        var response = req.CreateResponse(HttpStatusCode.OK);
        response.WriteString("ok");
        return response;
    }
}