Frequently Asked Questions

This guide answers common questions about VibeMQ.

General Questions 

What is VibeMQ?

VibeMQ is a simple but reliable message broker for .NET applications. It supports:

Publish/subscribe (pub/sub)
Queues with delivery guarantees
Automatic reconnections
username/password authentication
TLS/SSL encryption
Health checks for orchestrators

How is VibeMQ different from RabbitMQ/Kafka?

VibeMQ vs RabbitMQ:

VibeMQ is simpler to configure and use
Does not require external dependencies (databases, etc.)
Written in C# for .NET ecosystem
Less functionality, but sufficient for most scenarios

VibeMQ vs Kafka:

VibeMQ is not a distributed event log
Optional persistence via SQLite or Redis (see Persistence & Storage); default is in-memory
Simpler to deploy and use
Better suited for task queues and real-time notifications

When to use VibeMQ?

Good scenarios:

Task queues for background processing
Notifications between microservices
Real-time updates
Event-driven architecture
Distributed systems on .NET

Not suitable for:

Storing large volumes of data
Real-time streaming (use Kafka)
Complex message routing (use RabbitMQ)
Transactional messages

What .NET versions are supported?

.NET 8.0 (main target platform)
.NET 10.0 (support planned)

Technical Questions 

How does delivery guarantee work?

VibeMQ uses acknowledgment (ACK) mechanism:

Broker sends message to subscriber
ACK wait timer starts
Subscriber processes message and sends ACK
If ACK not received — retry delivery
After exhausting attempts — Dead Letter Queue

What happens when server restarts?

With in-memory storage (default):

Messages in queues are lost
Connections must be restored

With SQLite or Redis storage:

Queues and pending messages are recovered on startup (see Persistence & Storage).
Configure via BrokerBuilder.UseSqliteStorage(...) or UseRedisStorage(...) (or in Docker with VibeMQ__StorageType=Sqlite and the Host project).

How to scale VibeMQ?

Horizontal scaling:

Run multiple server instances
Use load balancer
Clients connect to nearest server

Vertical scaling:

Increase limits (MaxConnections, MaxQueueSize)
Add resources (CPU, RAM)

Planned:

Clustering for automatic scaling

How to ensure security?

Authentication:

.UseAuthorization(options => {
    options.SuperuserUsername = "admin";
    options.SuperuserPassword = "my-secret-password";
})

TLS encryption:

.UseTls(options => {
    options.Enabled = true;
    options.CertificatePath = "/path/to/cert.pfx";
})

Rate limiting:

.ConfigureRateLimiting(options => {
    options.Enabled = true;
    options.MaxConnectionsPerIpPerWindow = 100;
})

What delivery modes are supported?

Round-robin — to each subscriber in turn
Fan-out with ACK — to all with acknowledgment
Fan-out without ACK — to all without acknowledgment
Priority-based — by priority

How does Dead Letter Queue work?

DLQ stores messages that could not be delivered. Enable it when creating a queue (server queue defaults do not include DLQ options):

await client.CreateQueueAsync("my-queue", new QueueOptions {
    EnableDeadLetterQueue = true,
    MaxRetryAttempts = 3
});

Reasons for DLQ:

Exceeded delivery attempt count
Message TTL expired
Deserialization error
Exception in handler

Deployment 

How to run in Docker?

Dockerfile:

FROM mcr.microsoft.com/dotnet/runtime:8.0
WORKDIR /app
EXPOSE 2925 2926
COPY . .
ENTRYPOINT ["dotnet", "VibeMQ.Server.dll"]

Run:

docker pull bobsans/vibemq
docker run -p 2925:2925 -p 2926:2926 bobsans/vibemq

How to use with Kubernetes?

Deployment:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: vibemq
spec:
  replicas: 3
  selector:
    matchLabels:
      app: vibemq
  template:
    spec:
      containers:
      - name: vibemq
        image: bobsans/vibemq:latest
        ports:
        - containerPort: 2925
        - containerPort: 2926
        livenessProbe:
          httpGet:
            path: /health/
            port: 2926
          initialDelaySeconds: 10
          periodSeconds: 10

How to configure for production?

Recommendations:

var broker = BrokerBuilder.Create()
    .UsePort(2925)
    .UseAuthorization(options => {
    options.SuperuserUsername = "admin";
    options.SuperuserPassword = Environment.GetEnvironmentVariable("VIBEMQ_SUPERUSER_PASSWORD");
})
    .UseMaxConnections(5000)
    .ConfigureQueues(options => {
        options.DefaultDeliveryMode = DeliveryMode.FanOutWithAck;
        options.MaxQueueSize = 100_000;
    })
    .ConfigureRateLimiting(options => {
        options.Enabled = true;
        options.MaxConnectionsPerIpPerWindow = 100;
        options.MaxMessagesPerClientPerSecond = 5000;
    })
    .UseTls(options => {
        options.Enabled = true;
        options.CertificatePath = "/etc/ssl/vibemq.pfx";
    })
    .ConfigureHealthChecks(options => {
        options.Enabled = true;
        options.Port = 2926;
    })
    .Build();

Performance 

What is VibeMQ performance?

Benchmarks:

10,000+ messages/sec on single node
Latency < 10ms for 95% of messages
Support for 1000+ simultaneous connections

Factors affecting performance:

Message size
Number of subscribers
Delivery mode
Network latency

How to optimize performance?

On server:

.UseMaxConnections(5000)  // Increase limit
.ConfigureQueues(options => {
    options.MaxQueueSize = 100_000;  // Larger queue
})
// OverflowStrategy is set per-queue when creating with QueueOptions

On client:

new ClientOptions {
    KeepAliveInterval = TimeSpan.FromSeconds(60),  // Less frequent PING
    CommandTimeout = TimeSpan.FromSeconds(5)  // Lower timeout
}

General recommendations:

Use batching for publishing
Optimize message handlers
Monitor performance metrics

Security 

How secure is username/password authentication?

Recommendations:

Use complex passwords (12+ characters)
Store credentials in a secure location (Key Vault, Secrets Manager)
Rotate passwords periodically
Use different credentials for different environments

Warning

username/password authentication is suitable for internal security. For public APIs use OAuth2/OIDC.

Do I need to use TLS?

Yes, if:

Messages contain sensitive data
Network is untrusted
Security compliance required

No, if:

All services in trusted network
TLS terminates at load balancer level

How to protect against DDoS?

Rate limiting:

.ConfigureRateLimiting(options => {
    options.Enabled = true;
    options.MaxConnectionsPerIpPerWindow = 50;
    options.MaxMessagesPerClientPerSecond = 100;
})

Additionally:

Use firewall
Limit number of connections
Monitor anomalies

Integration 

How to use with ASP.NET Core?

using VibeMQ.Server.DependencyInjection;
using VibeMQ.Client.DependencyInjection;

var builder = WebApplication.CreateBuilder(args);

// Server
builder.Services.AddVibeMQBroker(options => {
    options.Port = 2925;
});

// Client
builder.Services.AddVibeMQClient(settings => {
    settings.Host = "localhost";
    settings.Port = 2925;
});

var app = builder.Build();
await app.RunAsync();

How to use with Worker Service?

using VibeMQ.Client.DependencyInjection;

var host = Host.CreateDefaultBuilder(args)
    .ConfigureServices(services => {
        services.AddHostedService<Worker>();
        services.AddVibeMQClient(settings => {
            settings.Host = "localhost";
            settings.Port = 2925;
        });
    })
    .Build();

await host.RunAsync();

Can I use with other languages?

Current version: Only .NET clients

Planned:

Clients for Java, Python, Node.js
AMQP/MQTT protocol support

Troubleshooting 

Why are messages lost?

Causes:

Server restarted (in-memory storage)
Message TTL expired
Queue size exceeded

Solution:

// Server defaults: limit queue size
.ConfigureQueues(options => {
    options.MaxQueueSize = 100_000;
})
// When creating queues: use QueueOptions with EnableDeadLetterQueue, MessageTtl

Why high latency?

Causes:

Server overload
Slow handlers
Network issues

Solution:

Optimize handlers
Increase server resources
Check network

Why frequent disconnections?

Causes:

Network issues
Keep-alive timeout
Server restarting

Solution:

new ClientOptions {
    ReconnectPolicy = new ReconnectPolicy {
        MaxAttempts = 50,  // Increase attempts
        UseExponentialBackoff = true
    },
    KeepAliveInterval = TimeSpan.FromSeconds(30)  // Check keep-alive
}

Next Steps 

Quick Start — quick start
Troubleshooting — troubleshooting
Examples — usage examples