Guinea-Bissau SMS Best Practices, Compliance, and Features

Guinea-Bissau SMS Market Overview

Market Conditions: Guinea-Bissau's mobile market is served by several key operators, with SMS remaining an important communication channel. The telecommunications sector is regulated by the Autoridade Reguladora Nacional das Tecnologias de Informação e Comunicação (ARN). While OTT messaging apps are gaining popularity in urban areas, SMS continues to be crucial for business communications and notifications due to its reliability and widespread accessibility.

Key SMS Features and Capabilities in Guinea-Bissau

Guinea-Bissau supports basic SMS functionality with some limitations on advanced features, requiring careful consideration for message delivery and compliance.

Two-way SMS Support

Two-way SMS is not supported in Guinea-Bissau according to current network capabilities. Businesses should design their messaging strategies around one-way communication flows.

Concatenated Messages (Segmented SMS)

Support: Yes, concatenated messages are supported, though with some limitations based on sender ID type.
Message length rules: Standard SMS length limits apply, with messages being split according to encoding type.
Encoding considerations: Both GSM-7 and UCS-2 encoding are supported, with UCS-2 specifically available for alphanumeric sender IDs.

MMS Support

MMS messages are not directly supported in Guinea-Bissau. Instead, MMS content is automatically converted to SMS with an embedded URL link where recipients can view the multimedia content. This ensures message delivery while maintaining media accessibility.

Recipient Phone Number Compatibility

Number Portability

Number portability is not available in Guinea-Bissau. This means phone numbers remain tied to their original mobile network operators, simplifying message routing but limiting consumer flexibility.

Sending SMS to Landlines

Sending SMS to landline numbers is not supported in Guinea-Bissau. Attempts to send messages to landline numbers will result in a 400 response error (code 21614) through the API, with no message delivery and no charging of the account.

Compliance and Regulatory Guidelines for SMS in Guinea-Bissau

SMS communications in Guinea-Bissau are regulated by the Autoridade Reguladora Nacional das Tecnologias de Informação e Comunicação (ARN). Businesses must comply with local telecommunications laws and data privacy regulations when sending SMS messages.

Consent and Opt-In

Explicit consent is mandatory before sending any marketing or non-essential communications to subscribers in Guinea-Bissau. Best practices for consent management include:

• Maintaining clear records of when and how consent was obtained
• Providing transparent information about message frequency and content
• Implementing double opt-in procedures for marketing campaigns
• Storing consent documentation securely for compliance purposes

HELP/STOP and Other Commands

All SMS campaigns must support standard opt-out commands including:

• STOP to unsubscribe
• HELP for assistance
• Commands should be recognized in both Portuguese and local languages
• Responses to these commands should be immediate and free of charge

Do Not Call / Do Not Disturb Registries

While Guinea-Bissau does not maintain an official Do Not Call registry, businesses should:

• Maintain their own suppression lists
• Honor opt-out requests immediately
• Document all opt-out requests for compliance purposes
• Regularly clean contact lists to remove unsubscribed numbers

Time Zone Sensitivity

Guinea-Bissau observes specific time restrictions for SMS communications:

• Restricted Hours: No SMS between 10 PM and 6 AM unless explicitly requested
• Daily Limit: Maximum of three SMS messages per day per recipient
• Best Practice: Schedule messages between 9 AM and 8 PM local time

Phone Numbers Options and SMS Sender Types for in Guinea-Bissau

Alphanumeric Sender ID

Operator network capability: Supported with pre-registration required
Registration requirements: Global pre-registration mandatory, no dynamic usage supported
Sender ID preservation: Yes, preserved when properly registered
Provisioning time: Approximately 3 weeks
Special note: MTN network only supports pre-registered alphanumeric sender IDs

Long Codes

Domestic vs. International:

• Domestic long codes: Supported by operators but not available through major providers
• International long codes: Supported with limitations on MTN network

Sender ID preservation: Yes, for international long codes
Use cases: Recommended for transactional messages and two-factor authentication

Short Codes

Support: Not currently supported in Guinea-Bissau
Use cases: N/A - businesses should use alternative sender ID types

Restricted SMS Content, Industries, and Use Cases

The following content types and industries face restrictions:

• Gambling and betting services
• Adult content and services
• Political messaging without proper authorization
• Religious content
• Alcohol and tobacco products
• Unauthorized financial services

Content Filtering

Known carrier filtering rules:

• Messages containing restricted keywords are automatically blocked
• URLs may trigger additional scrutiny
• High-frequency messaging patterns may be filtered

Best practices to avoid filtering:

• Avoid common spam trigger words
• Use registered and approved sender IDs
• Maintain consistent sending patterns
• Include clear business identification in messages

Best Practices for Sending SMS in Guinea-Bissau

Messaging Strategy

• Keep messages under 160 characters when possible
• Include clear call-to-actions
• Identify your business in each message
• Use personalization thoughtfully to increase engagement

Sending Frequency and Timing

• Respect the three-message daily limit
• Space messages throughout the day
• Avoid sending during religious holidays
• Consider local business hours and customs

Localization

• Primary languages: Portuguese and Creole
• Consider bilingual messages for important communications
• Use local date and time formats
• Respect cultural sensitivities in message content

Opt-Out Management

• Process opt-outs within 24 hours
• Maintain accurate opt-out records
• Provide clear opt-out instructions in messages
• Confirm opt-out requests with a final confirmation message

Testing and Monitoring

• Test messages across all major carriers
• Monitor delivery rates by carrier
• Track opt-out rates and patterns
• Regular review of message performance metrics

SMS API integrations for Guinea-Bissau

Twilio

Twilio provides a robust SMS API for sending messages to Guinea-Bissau. Here's how to implement it:

import { Twilio } from 'twilio';

// Initialize the client with your credentials
const client = new Twilio(
  process.env.TWILIO_ACCOUNT_SID,
  process.env.TWILIO_AUTH_TOKEN
);

// Function to send SMS to Guinea-Bissau
async function sendSMSToGuineaBissau(
  to: string,
  message: string,
  senderId: string
) {
  try {
    // Ensure proper formatting for Guinea-Bissau numbers (+245)
    const formattedNumber = to.startsWith('+245') ? to : `+245${to}`;
    
    const response = await client.messages.create({
      body: message,
      from: senderId, // Pre-registered alphanumeric sender ID
      to: formattedNumber,
      // Optional parameters for delivery tracking
      statusCallback: 'https://your-webhook-url.com/status'
    });
    
    console.log(`Message sent successfully! SID: ${response.sid}`);
    return response;
  } catch (error) {
    console.error('Error sending message:', error);
    throw error;
  }
}

Sinch

Sinch offers SMS capabilities for Guinea-Bissau with their unified SDK:

import { SinchClient } from '@sinch/sdk-core';

// Initialize Sinch client
const sinchClient = new SinchClient({
  projectId: process.env.SINCH_PROJECT_ID,
  keyId: process.env.SINCH_KEY_ID,
  keySecret: process.env.SINCH_KEY_SECRET
});

// Function to send SMS using Sinch
async function sendSinchSMS(
  recipientNumber: string,
  messageText: string
) {
  try {
    const response = await sinchClient.sms.batches.send({
      sendSMSRequestBody: {
        to: [recipientNumber], // Must include country code +245
        from: "YourBrand", // Your registered sender ID
        body: messageText,
        // Optional delivery report URL
        deliveryReport: "URL"
      }
    });
    
    console.log('Message sent:', response);
    return response;
  } catch (error) {
    console.error('Sinch SMS Error:', error);
    throw error;
  }
}

MessageBird (Bird)

MessageBird's API implementation for Guinea-Bissau:

import { MessageBird } from 'messagebird';

// Initialize MessageBird client
const messagebird = MessageBird(process.env.MESSAGEBIRD_API_KEY);

// Function to send SMS via MessageBird
async function sendMessageBirdSMS(
  to: string,
  message: string,
  senderId: string
): Promise<any> {
  return new Promise((resolve, reject) => {
    messagebird.messages.create({
      originator: senderId,
      recipients: [to], // Must include +245 prefix
      body: message,
      // Optional parameters
      reportUrl: 'https://your-webhook-url.com/status',
      validity: 24 // Message validity in hours
    }, (err, response) => {
      if (err) {
        reject(err);
      } else {
        resolve(response);
      }
    });
  });
}

API Rate Limits and Throughput

When sending SMS to Guinea-Bissau, consider these limitations:

• Daily Limits: Maximum 3 messages per recipient per day
• Throughput: Varies by carrier, typically 10-30 messages per second
• Batch Processing: Recommended batch size of 500 messages
• Retry Logic: Implement exponential backoff for failed messages

Best Practices for High Volume Sending:

• Implement message queuing systems
• Use batch APIs when available
• Monitor delivery rates and adjust sending speed
• Implement rate limiting in your application

Error Handling and Reporting

Common Error Scenarios:

• Invalid phone number format
• Exceeded daily message limit
• Network connectivity issues
• Sender ID registration problems

Recommended Logging Practices:

interface SMSLogEntry {
  messageId: string;
  recipient: string;
  timestamp: Date;
  status: string;
  errorCode?: string;
  retryCount?: number;
}

// Example logging function
function logSMSActivity(entry: SMSLogEntry): void {
  // Log to your preferred system (e.g., CloudWatch, DataDog)
  console.log(JSON.stringify(entry));
}

Recap and Additional Resources

Key Takeaways

1. Compliance Requirements:

   • Pre-register alphanumeric sender IDs
   • Respect time restrictions (no SMS between 10 PM - 6 AM)
   • Maximum 3 messages per day per recipient

2. Technical Considerations:

   • Always use international number format (+245)
   • Implement proper error handling
   • Monitor delivery rates

3. Best Practices:

   • Maintain opt-out lists
   • Use queuing for high-volume sending
   • Regular testing across carriers

Next Steps

1. Technical Setup:

   • Register with preferred SMS provider
   • Set up sender ID registration
   • Implement delivery tracking

2. Compliance:

   • Review ARN regulations
   • Consult legal counsel
   • Document consent processes

3. Testing:

   • Verify delivery across carriers
   • Test opt-out functionality
   • Monitor delivery rates

Additional Resources

• ARN Official Website
• Guinea-Bissau Telecommunications Law
• [SMS Provider Documentation]:
  • Twilio Guinea-Bissau Guide
  • Sinch SMS API Documentation
  • MessageBird API Reference