In high-concurrency multi-tenant SaaS platforms without granular rate limiting, a single rogue or misconfigured tenant can take down the entire cluster:

Noisy Neighbor Effect: Tenant A runs an aggressive scraper exhausting the database connection pool, causing requests for Tenant B to time out;
Credential Stuffing Attacks: Bots attacking authentication endpoints causing server CPUs to spike to 100%.

BitzOrcas.Modern incorporates fine-grained rate limiting policies partitioned by tenant and IP: Supporting Sliding Window, Token Bucket, and concurrency queues, returning standard HTTP 429 Too Many Requests.

Multi-Tenant Rate Limiting and Partition Lifecycle

Step 1: Binding Rate Limiting Policies on Endpoints

Bind predefined policies on commands using [GenerateEndpoint]:

using BitzOrcas.Domain.Results;
using BitzOrcas.Endpoint.Attributes;
using Mediator;

namespace BitzOrcas.Identity.Application.Commands;

// 1. Binds strict SMS verification rate limiting policy (max 3 requests per minute per IP)
[GenerateEndpoint(
    HttpRoute.Post,
    "/api/auth/send-code",
    Tag = "Auth",
    RateLimitPolicy = "smsVerificationPolicy")]
// 2. Contract record mapped to Minimal API with automated rate limiting guard
public sealed record SendVerificationCodeCommand(string PhoneNumber) : ICommand<Result>;

Step 2: Configuring Tenant-Aware Rate Limit Partitions

using System.Threading.RateLimiting;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.DependencyInjection;

public static class RateLimitingConfiguration
{
    public static IServiceCollection AddAppRateLimiting(this IServiceCollection services)
    {
        // Register standard ASP.NET Core RateLimiter
        services.AddRateLimiter(options =>
        {
            // Configure sliding window for verification codes
            options.AddPolicy("smsVerificationPolicy", httpContext =>
            {
                // 1. Partition rate limiter by client IP address
                var clientIp = httpContext.Connection.RemoteIpAddress?.ToString() ?? "unknown";

                return RateLimitPartition.GetSlidingWindowLimiter(
                    partitionKey: $"sms:{clientIp}",
                    factory: _ => new SlidingWindowRateLimiterOptions
                    {
                        PermitLimit = 3,
                        Window = TimeSpan.FromMinutes(1),
                        SegmentsPerWindow = 6,
                        QueueLimit = 0
                    });
            });

            // Return standard 429 status code
            options.RejectionStatusCode = StatusCodes.Status429TooManyRequests;
        });

        return services;
    }
}

Summary

BitzOrcas rate limiting shields production clusters:

Noisy Neighbor Elimination: Dynamic tenant and IP partitions safeguard cluster health;
Native AOT Ready: Built directly on .NET 10 System.Threading.RateLimiting with zero reflection;
Standard Protocol Compliance: 429 status and Retry-After headers instruct clients on safe retry intervals.