MQTT Authentication

MQTT Authentication

SiliconWit.IO requires authentication for all MQTT connections to ensure your data stays secure.

Authentication Method

Every device uses username/password authentication:

Field	Value
Username	Your Device ID
Password	Your Access Token
Client ID	Your Device ID

Getting Credentials

1. Log in to your Dashboard
2. Go to Devices → Select your device
3. Find your Device ID (always visible)
4. Click Reveal Token to see your Access Token

Caution

Your Access Token is only shown once when you create a device. If you lose it, you’ll need to regenerate it (which invalidates the old token).

Connection Example

const char* device_id = "dev_a1b2c3d4e5f6";
const char* access_token = "tok_xxxxxxxxxxxxxxxxxxxxxxxx";

// Connect with authentication
client.connect(device_id, device_id, access_token);

TLS Encryption

For production deployments, use TLS to encrypt your connection:

Port 8883 (MQTT over TLS)

#include <WiFiClientSecure.h>

WiFiClientSecure secureClient;
PubSubClient mqtt(secureClient);

void setup() {
  // For testing (accepts any certificate)
  secureClient.setInsecure();

  // For production (verify server certificate)
  // secureClient.setCACert(root_ca_cert);

  mqtt.setServer("mqtt.siliconwit.io", 8883);
}

WebSocket Secure (WSS)

For browser or WebSocket clients:

wss://mqtt.siliconwit.io:8084/mqtt

Topic Authorization

Devices can only access their own topics:

Allowed	Not Allowed
devices/{your-id}/telemetry	devices/{other-id}/telemetry
devices/{your-id}/commands	devices/+/telemetry
devices/{your-id}/status	#

Attempting to publish or subscribe to unauthorized topics will fail silently or disconnect the client.

Token Security Best Practices

Do

• Store tokens in secure storage or environment variables
• Use TLS in production
• Rotate tokens periodically
• Use unique tokens per device

Don’t

• Hardcode tokens in source code (use config files)
• Share tokens between devices
• Log or print tokens
• Send tokens over unencrypted connections

Regenerating Tokens

If a token is compromised:

1. Go to Dashboard → Devices → Select device
2. Click Security tab
3. Click Regenerate Token
4. Update your device with the new token

Regenerating a token immediately invalidates the old one. Your device will disconnect until updated.

API Key Authentication

For server-to-server communication, use API keys instead:

curl -X POST https://api.siliconwit.io/v1/devices/abc123/telemetry \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"temperature": 25.5}'

API keys are managed in Dashboard → Settings → API Keys.

Connection Limits

Plan	Concurrent Connections
Starter	3
Business	50
Enterprise	Unlimited

Each device can have one active MQTT connection. Opening a new connection with the same credentials will disconnect the previous one.

Troubleshooting

Connection Refused (Error 5)

• Cause: Invalid username or password
• Fix: Verify Device ID and Access Token are correct

Connection Lost Repeatedly

• Cause: Another client using same credentials
• Fix: Ensure only one connection per device

TLS Handshake Failed

• Cause: Certificate verification failed
• Fix: Update device time (NTP), or use setInsecure() for testing

Next Steps

• MQTT Basics - Protocol fundamentals
• Quick Start - Get connected