Montserrat SMS Guide: Compliance, Best Practices & API Integration

Understanding the Montserrat SMS Market

Market Conditions: Montserrat is a British Overseas Territory in the Caribbean with a small but competitive mobile market. Two main mobile operators serve the island: Flow (Cable & Wireless, the incumbent operator established pre-2015) and Digicel (entered the market in 2015). Flow maintains broader coverage across inhabited areas, while Digicel offers 4G/LTE services (since late 2017) alongside 2G and 3G networks. While OTT (Over-The-Top) messaging apps like WhatsApp are popular among residents, SMS remains critical for business communications, emergency alerts, and reaching areas with limited data connectivity. Android devices hold a slight edge over iOS in market share.

Population & Subscriber Statistics (January 2025): Montserrat's population is approximately 4,373, with 9,181 active cellular mobile connections representing 210% penetration – many residents use multiple devices for personal and work purposes. Internet penetration stands at 55.9% (2,444 users), while 92.4% of mobile connections support 3G, 4G, or 5G broadband networks.

SMS Pricing Considerations: International SMS API providers charge approximately $0.2371 per message segment for Montserrat (Twilio), with other providers like Plivo ($0.0035–$0.007) and Sinch ($0.0096–$0.0192) offering competitive base rates. Local providers Flow and Digicel offer bundled SMS packages (typically 100 SMS for EC$ 5–10 prepaid, or up to 500 SMS for EC$ 50–75 postpaid). Higher volumes typically qualify for tiered discounts from all providers.

SMS Features and Capabilities in Montserrat

Montserrat supports basic SMS functionality with some limitations on advanced features, following UK-influenced telecommunications standards while maintaining its unique infrastructure requirements.

Two-Way SMS Support

Major SMS providers do not support two-way SMS in Montserrat according to current specifications. You can send messages to users but cannot receive replies through the same channel.

Why Two-Way SMS Isn't Supported: Carrier infrastructure and routing configurations in Montserrat's telecommunications network create this limitation. Both Flow and Digicel networks do not support inbound message routing to international SMS gateways.

Alternative Methods for Customer Responses:

• Include web form links in your messages for structured feedback
• Direct customers to WhatsApp Business numbers for two-way conversations
• Use email addresses for detailed responses
• Provide phone numbers for voice callback options
• Implement QR codes linking to response portals
• Use social media handles (Facebook, Instagram) for engagement

Concatenated Messages (Segmented SMS)

Support: Montserrat does not support concatenated messages. Message length rules: Standard SMS length limits apply – 160 characters for GSM-7 encoding and 70 characters for Unicode. Encoding considerations: Both GSM-7 and Unicode (UCS-2) encodings are supported, but keep your messages within single-message length limits.

Character Counting Examples:

• "Hello! Your appointment is confirmed for tomorrow at 2pm." (58 characters, GSM-7) ✓
• "Your verification code is: 123456" (34 characters, GSM-7) ✓
• "🎉 Welcome! Your account is ready." (36 characters, but contains emoji → Unicode/UCS-2, counted as 36 characters) ✓
• Messages with curly quotes (", "), em dashes (—), or special symbols trigger Unicode encoding, reducing your limit to 70 characters

What Happens If You Exceed Character Limits: When you attempt to send a message exceeding the character limit in Montserrat, the API returns an error (commonly Twilio error 21614 or similar provider-specific codes). The message is not delivered, does not appear in logs, and you are not charged. Validate message length before sending to avoid delivery failures.

MMS Support

The system automatically converts MMS messages to SMS with an embedded URL link. This conversion ensures message delivery while providing access to multimedia content through web links. Use short URLs and include clear instructions for accessing the content.

MMS-to-SMS Conversion Example: Original MMS intent: Image + "Check out our new menu!" Converted SMS output: "Check out our new menu! View image: https://short.link/abc123"

Best Practices for MMS Conversion:

• Use reputable URL shorteners (Bitly, TinyURL, or provider-managed shorteners)
• Host images on reliable, fast-loading servers
• Keep combined text + URL under 160 characters
• Test links before sending campaigns
• Use descriptive link text: "View menu" instead of generic "Click here"
• Ensure mobile-optimized landing pages

Recipient Phone Number Compatibility

Number Portability

Montserrat does not offer number portability. Mobile numbers are tied to specific carriers, simplifying message routing but limiting consumer flexibility in changing providers while keeping their numbers.

Sending SMS to Landlines

You cannot send SMS to landline numbers in Montserrat. Attempts to send messages to landline numbers result in a 400 response with error code 21614. The message does not appear in logs, and you are not charged.

Montserrat SMS Compliance: MICA Regulations and Requirements

Montserrat has its own data protection framework separate from UK GDPR, though it follows similar principles. The Montserrat Info-Communications Authority (MICA), established August 1, 2009, regulates telecommunications services under the Info-Communications Development Act 2009. Comply with Montserrat's local data protection requirements, which are influenced by UK and EU data protection principles.

Penalties for Non-Compliance: Under the Telecommunications Act and Info-Communications Development Act, violations result in fines up to EC$ 2,000 and imprisonment for up to three months, or both. MICA has authority to impose additional penalties including license suspension, service restrictions, and ongoing compliance audits. Businesses also face reputational damage and customer loss.

Key Differences from UK GDPR: While Montserrat's data protection principles align with UK standards, enforcement mechanisms and specific thresholds differ. Montserrat maintains independent regulatory authority through MICA rather than the UK ICO. Consent requirements, data retention policies, and breach notification timelines follow the Info-Communications Development Act 2009 rather than UK GDPR articles directly.

Consent and Opt-In

Explicit Consent Requirements:

• Obtain clear, specific consent before sending marketing messages
• Maintain detailed records of when and how you obtained consent
• Separate consent for different types of communications (marketing, transactional, etc.)
• Provide clear terms and conditions at the point of opt-in

Best Practices for Documentation:

• Store consent records with timestamp and source
• Keep proof of opt-in method (web form, text keyword, etc.)
• Regularly audit and clean up your consent records
• Enable double opt-in for additional security

Consent Record Retention: Maintain consent documentation for a minimum of 3 years after the last communication, or longer if required by your industry regulations. Include: timestamp, IP address, opt-in method, explicit consent language shown to user, and any subsequent opt-in confirmations.

HELP/STOP and Other Commands

• Required Keywords: STOP, CANCEL, UNSUBSCRIBE, END, QUIT
• Optional Support: HELP, INFO
• Language Requirements: English is the primary language; no local language requirements
• Response Time: Process opt-out requests within 24 hours

Do Not Call / Do Not Disturb Registries

Montserrat does not maintain a separate Do Not Call registry. You should:

• Maintain your own suppression lists
• Honor opt-out requests immediately
• Regularly update your contact lists
• Remove inactive or bounced numbers
• Document all opt-out requests with timestamps

Time Zone Sensitivity

Montserrat follows Atlantic Standard Time (AST/UTC-4) year-round and does not observe daylight saving time.

• Recommended Sending Hours: 8:00 AM to 8:00 PM AST
• Emergency Messages: Send outside standard hours only when truly urgent
• Holiday Considerations: Respect local holidays and weekends
• Best Practice: Schedule campaigns during business hours (9:00 AM to 5:00 PM)

Choosing Your SMS Sender ID for Montserrat

Alphanumeric Sender ID

Operator network capability: Supported with dynamic usage Registration requirements: No pre-registration required Sender ID preservation: Carriers generally preserve sender IDs but may modify them for security

Character Limits and Formatting Rules: Alphanumeric sender IDs support 3–11 characters maximum. Accepted characters include uppercase and lowercase letters (A-Z, a-z), digits (0-9), and spaces (ASCII code 32). The sender ID cannot be all numeric – must contain at least one letter. Avoid special characters (!@#$%^&*).

Acceptable vs. Unacceptable Examples:

• ✓ Acceptable: "YourBrand", "Alert123", "FlowMSR", "INFO2025"
• ✗ Unacceptable: "12345" (all numeric), "Brand!" (special character), "AB" (too short), "VERYLONGNAME" (exceeds 11 chars)

What "Modify for Security" Means: Carriers may replace sender IDs that resemble emergency services (911, POLICE), financial institutions, or government agencies to prevent spoofing and fraud. They may also block sender IDs containing offensive terms or those flagged in spam databases.

Long Codes

Domestic vs. International:

• Domestic long codes: Supported
• International long codes: Not supported for A2P messaging

Sender ID preservation: System preserves original sender ID for domestic numbers Provisioning time: 1–2 business days Use cases: Ideal for transactional messages and customer support

Cost Comparison: Alphanumeric sender IDs typically cost the same per message as long codes ($0.20–$0.24 per segment) but offer better brand recognition. Long codes require upfront provisioning fees (typically $1–$5/month per number) plus per-message costs, but enable potential two-way messaging support in future network upgrades.

Provisioning Process:

1. Select your SMS API provider (Twilio, Sinch, Plivo, etc.)
2. Submit number request through provider's console
3. Provide business documentation (registration, use case description)
4. Wait 1–2 business days for carrier approval
5. Configure number in your application
6. Test with small volume before scaling

Short Codes

Support: Not currently supported in Montserrat Provisioning time: N/A Use cases: N/A

What Content Can You Send via SMS in Montserrat?

Restricted Industries:

• Gambling and betting services
• Adult content
• Cryptocurrency promotions
• Unregistered financial services
• Unauthorized healthcare products

Regulated Industries:

• Financial services require regulatory approval
• Healthcare messages must comply with privacy standards
• Insurance products need proper disclaimers

Consequences of Violations: Content restriction violations result in immediate message blocking, account suspension (temporary or permanent), fines from MICA up to EC$ 2,000, and termination of SMS service agreements. Repeated violations may trigger investigation by MICA and potential legal action under the Info-Communications Development Act 2009.

Regulatory Approval for Financial Services: Financial institutions must obtain licensing from the Montserrat Financial Services Commission and register their SMS campaigns with MICA. Required documentation includes: business license, compliance officer details, message templates for review, opt-in processes, and data protection policies. Approval typically takes 2–4 weeks.

Compliant vs. Non-Compliant Message Examples:

• ✓ Compliant: "YourBank: Your account balance is $1,234.56. Questions? Call 1-664-XXX-XXXX"
• ✗ Non-Compliant: "🚨URGENT! Invest in crypto NOW! 500% returns guaranteed! bit.ly/xyz"
• ✓ Compliant: "HealthClinic: Appointment reminder for Jan 15 at 2pm. Reply C to confirm."
• ✗ Non-Compliant: "Buy Viagra cheap! No prescription needed! Order now!"

Content Filtering

Known Carrier Filters:

• URLs from unknown domains
• Multiple exclamation marks
• ALL CAPS messages
• Excessive special characters

Best Practices to Avoid Filtering:

• Use registered URL shorteners
• Maintain consistent sender IDs
• Avoid spam trigger words
• Keep message formatting simple

Common Spam Trigger Words to Avoid: Based on industry standards for SMS filtering, avoid these high-risk terms:

• Urgency: "Act now", "Limited time", "Urgent", "Don't miss out", "Once in a lifetime"
• Financial: "Free money", "Cash bonus", "Make $$$", "Earn extra cash", "Financial freedom"
• Guarantees: "Guaranteed", "Risk-free", "No obligation", "100% free", "Satisfaction guaranteed"
• Prizes: "Winner", "Jackpot", "Cash prize", "You've won", "Congratulations"
• Excessive punctuation: "!!!", "$$$", "***"

Troubleshooting Filtered Messages: If messages are blocked: (1) Review content for spam trigger words; (2) Check sender ID isn't flagged; (3) Verify URLs are from trusted domains; (4) Contact your SMS provider for delivery reports; (5) Request carrier feedback through your provider; (6) Test with simplified message content; (7) Appeal blocks by providing business documentation and compliance evidence to MICA.

Filtering Impact: Industry data suggests 5–15% of messages containing multiple spam triggers may be filtered or delayed. Messages with clean content, consistent sender IDs, and established sending patterns typically achieve 95%+ delivery rates.

Best Practices for SMS Campaigns in Montserrat

Messaging Strategy

• Keep messages under 160 characters
• Include clear call-to-action
• Use personalization tokens wisely
• Maintain consistent brand voice

Message Templates and Examples:

Before (poor): "HEY!!! Check out our AMAZING deals NOW! Click here: bit.ly/xyz Limited time only!!!"

After (good): "Hi Sarah, 20% off all items this week at FlowShop. Shop now: flowshop.ms/sale"

Before (poor): "Your package will arrive between 8am-6pm on Monday or Tuesday depending on weather and traffic conditions and other factors"

After (good): "YourBrand: Package arrives Mon-Tue. Track here: track.ms/abc123"

Personalization Token Implementation: Most SMS APIs support merge fields like {{first_name}}, {{order_id}}, or {{balance}}. Example: "Hi {{first_name}}, your order #{{order_id}} shipped today." Limitations: (1) Validate all tokens have values before sending; (2) Account for varying field lengths in character counts; (3) Provide fallbacks for missing data (e.g., "Hi there" if name unavailable); (4) Test thoroughly to avoid broken messages.

Sending Frequency and Timing

• Limit to 2–4 messages per month per recipient
• Respect local holidays and events
• Avoid early morning/late night sending
• Space out campaigns appropriately

Localization

• Use standard English
• Avoid colloquialisms
• Consider cultural context
• Use local date/time formats

Opt-Out Management

• Include opt-out instructions in every message
• Process opt-outs within 24 hours
• Maintain clean suppression lists
• Confirm opt-out with final message

Testing and Monitoring

• Test across major local carriers
• Monitor delivery rates daily
• Track engagement metrics
• Regular A/B testing of message content

Acceptable Delivery Rate Thresholds:

• Excellent: 95%+ delivery rate
• Good: 90–95% delivery rate
• Needs attention: 85–90% delivery rate (investigate content filtering, sender ID issues)
• Poor: Below 85% delivery rate (immediate action required – review compliance, contact provider)

Setting Up Monitoring Infrastructure:

1. Configure webhook endpoints for delivery receipts (status callbacks)
2. Store delivery data in database (timestamp, status, provider response codes)
3. Set up alerting for delivery rates below 90% (email, Slack, PagerDuty)
4. Create dashboards tracking: daily send volume, delivery %, bounce %, opt-out rate
5. Schedule weekly reports analyzing trends and anomalies
6. Implement automated testing of sample messages to both carriers

Sample Monitoring Checklist:

• Webhook receiving delivery reports (test daily)
• Dashboard showing delivery rates per carrier
• Alerts configured for <90% delivery
• Weekly review of bounce reasons
• Monthly audit of message content against spam triggers
• Quarterly compliance review with legal team

Top SMS APIs for Montserrat Integration

Twilio

Twilio provides robust SMS capabilities for sending messages to Montserrat through their REST API.

Authentication Requirements:

• Account SID
• Auth Token
• Verified Twilio phone number

import { Twilio } from 'twilio';

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

async function sendSMSToMontserrat(
  to: string,
  message: string,
  from: string
): Promise<void> {
  try {
    // Validate input
    if (!to || !message || !from) {
      throw new Error('Missing required parameters: to, message, or from');
    }

    // Validate message length (160 for GSM-7)
    if (message.length > 160) {
      throw new Error(`Message exceeds 160 characters (${message.length}). Montserrat does not support concatenated messages.`);
    }

    // Ensure number is in E.164 format for Montserrat (+1664XXXXXXX)
    const formattedNumber = to.startsWith('+1664') ? to : `+1664${to}`;

    // Validate phone number format (must be +1664 followed by 7 digits)
    const phoneRegex = /^\+1664\d{7}$/;
    if (!phoneRegex.test(formattedNumber)) {
      throw new Error('Invalid Montserrat phone number format. Expected: +1664XXXXXXX');
    }

    const response = await client.messages.create({
      body: message,
      from: from,  // Your Twilio number or approved sender ID
      to: formattedNumber,
      // Optional: statusCallback URL for delivery updates
      statusCallback: 'https://your-webhook.com/status'
    });

    console.log(`Message sent successfully! SID: ${response.sid}`);
  } catch (error) {
    // Handle common Twilio errors for Montserrat
    if (error.code === 21614) {
      console.error('Cannot send to landline number in Montserrat');
    } else if (error.code === 21211) {
      console.error('Invalid phone number format');
    } else if (error.code === 21408) {
      console.error('Permission to send to this destination not enabled');
    }
    console.error('Error sending message:', error);
    throw error;
  }
}

// Example webhook handler for status callbacks
app.post('/status', (req, res) => {
  const { MessageSid, MessageStatus, ErrorCode } = req.body;

  console.log(`Message ${MessageSid} status: ${MessageStatus}`);

  if (ErrorCode) {
    console.error(`Error code: ${ErrorCode}`);
    // Store error for analysis
  }

  res.sendStatus(200);
});

Common Twilio Error Codes for Montserrat:

• 21211: Invalid 'To' phone number format
• 21408: Permission to send SMS not enabled for destination
• 21610: Attempt to send to unsubscribed recipient
• 21614: Cannot send SMS to landline number
• 30001: Queue overflow (rate limit exceeded)
• 30002: Account suspended
• 30003: Unreachable destination handset
• 30005: Unknown destination handset
• 30006: Landline or unreachable carrier

Sinch

Sinch offers SMS API access with support for Montserrat destinations through their REST API.

import axios from 'axios';

interface SinchSMSResponse {
  id: string;
  status: string;
}

async function sendSinchSMS(
  to: string,
  message: string,
  senderId: string
): Promise<SinchSMSResponse&gt; {
  const SINCH_API_TOKEN = process.env.SINCH_API_TOKEN;
  const SERVICE_PLAN_ID = process.env.SINCH_SERVICE_PLAN_ID;

  try {
    const response = await axios.post(
      `https://sms.api.sinch.com/xms/v1/${SERVICE_PLAN_ID}/batches`,
      {
        from: senderId,
        to: [to],
        body: message
      },
      {
        headers: {
          'Authorization': `Bearer ${SINCH_API_TOKEN}`,
          'Content-Type': 'application/json'
        }
      }
    );

    return response.data;
  } catch (error) {
    console.error('Sinch SMS Error:', error);
    throw error;
  }
}

MessageBird

MessageBird provides SMS capabilities for Montserrat through their REST API.

import messagebird from 'messagebird';

class MessageBirdService {
  private client: any;

  constructor(apiKey: string) {
    this.client = messagebird(apiKey);
  }

  async sendSMS(
    to: string,
    message: string,
    originator: string
  ): Promise<any&gt; {
    return new Promise((resolve, reject) =&gt; {
      this.client.messages.create({
        originator: originator,
        recipients: [to],
        body: message,
        // Optional parameters
        reportUrl: 'https://your-webhook.com/delivery-reports'
      }, (err: any, response: any) =&gt; {
        if (err) {
          reject(err);
        } else {
          resolve(response);
        }
      });
    });
  }
}

Plivo

Plivo offers SMS integration for Montserrat with their REST API.

import plivo from 'plivo';

class PlivoService {
  private client: any;

  constructor(authId: string, authToken: string) {
    this.client = new plivo.Client(authId, authToken);
  }

  async sendSMS(
    to: string,
    message: string,
    from: string
  ): Promise<any&gt; {
    try {
      const response = await this.client.messages.create({
        src: from,
        dst: to,
        text: message,
        // Optional parameters
        url: 'https://your-webhook.com/status',
        method: 'POST'
      });

      return response;
    } catch (error) {
      console.error('Plivo SMS Error:', error);
      throw error;
    }
  }
}

API Rate Limits and Throughput

Rate Limits:

• Twilio: 250 messages per second
• Sinch: 30 messages per second
• MessageBird: 60 messages per second
• Plivo: 50 messages per second

Throughput Management Strategies:

• Implement queue systems (Redis/RabbitMQ)
• Use batch sending APIs where available
• Implement exponential backoff for retries
• Monitor delivery rates and adjust sending speed

What Happens When Rate Limits Are Exceeded: Providers return HTTP 429 (Too Many Requests) errors. Messages are not sent, not charged, and must be retried. Repeated violations may result in temporary account restrictions. Implement exponential backoff: wait 1 second, then 2s, 4s, 8s before retrying.

Queue System Implementation Example:

import Queue from 'bull';
import Redis from 'ioredis';

// Create Redis-backed queue
const smsQueue = new Queue('montserrat-sms', {
  redis: {
    host: process.env.REDIS_HOST,
    port: 6379
  }
});

// Process messages with rate limiting
smsQueue.process(5, async (job) => {
  const { to, message, from } = job.data;

  try {
    await sendSMSToMontserrat(to, message, from);
    return { success: true };
  } catch (error) {
    // Retry logic handled by Bull
    throw error;
  }
});

// Add message to queue
async function queueSMS(to: string, message: string, from: string) {
  await smsQueue.add(
    { to, message, from },
    {
      attempts: 3,
      backoff: {
        type: 'exponential',
        delay: 2000
      }
    }
  );
}

Error Handling and Reporting

Best Practices:

• Implement comprehensive error logging
• Set up webhook endpoints for delivery reports
• Monitor message statuses in real-time
• Store delivery receipts for audit purposes

// Example error handling implementation
interface SMSError {
  code: string;
  message: string;
  timestamp: Date;
  provider: string;
}

// Determine if error is retryable
function isRetryableError(error: SMSError): boolean {
  const retryableCodes = [
    '30001', // Queue overflow
    '30003', // Unreachable handset (temporary)
    '429',   // Rate limit
    'ETIMEDOUT',
    'ECONNRESET'
  ];

  return retryableCodes.includes(error.code);
}

// Queue for retry with exponential backoff
async function queueForRetry(error: SMSError, messageData: any, attempt: number = 1): Promise<void&gt; {
  const maxAttempts = 3;
  const baseDelay = 2000; // 2 seconds

  if (attempt &gt; maxAttempts) {
    await logger.error('Max retry attempts reached', { error, messageData });
    // Move to dead letter queue or alert ops team
    return;
  }

  const delay = baseDelay * Math.pow(2, attempt - 1);

  await logger.info(`Scheduling retry attempt ${attempt} after ${delay}ms`, { error });

  setTimeout(async () =&gt; {
    try {
      await sendSMSToMontserrat(
        messageData.to,
        messageData.message,
        messageData.from
      );
    } catch (retryError) {
      if (isRetryableError(retryError)) {
        await queueForRetry(retryError, messageData, attempt + 1);
      } else {
        await logger.error('Non-retryable error on retry', { retryError });
      }
    }
  }, delay);
}

async function handleSMSError(error: SMSError, messageData?: any): Promise<void&gt; {
  // Log to monitoring system
  await logger.error('SMS Error', {
    ...error,
    service: 'sms-service',
    country: 'Montserrat',
    messageData
  });

  // Implement retry logic if needed
  if (isRetryableError(error) && messageData) {
    await queueForRetry(error, messageData);
  } else {
    // Non-retryable error - notify operations team
    await notifyOpsTeam({
      severity: 'high',
      error,
      messageData
    });
  }
}

// Complete error handling workflow
async function sendWithErrorHandling(to: string, message: string, from: string) {
  try {
    await sendSMSToMontserrat(to, message, from);
  } catch (error) {
    const smsError: SMSError = {
      code: error.code || 'UNKNOWN',
      message: error.message,
      timestamp: new Date(),
      provider: 'twilio'
    };

    await handleSMSError(smsError, { to, message, from });
  }
}

Frequently Asked Questions

How do I send SMS to Montserrat?

Send SMS to Montserrat by: (1) Choosing between alphanumeric sender IDs (no registration required) or domestic long codes (1–2 business days provisioning); (2) Integrating with an SMS API provider like Twilio, Sinch, MessageBird, or Plivo; (3) Formatting recipient numbers in E.164 format (+1664XXXXXXX); and (4) Ensuring compliance with MICA regulations and obtaining explicit opt-in consent from recipients.

What is the country code for sending SMS to Montserrat?

The country code for Montserrat is +1664. Format phone numbers in E.164 format: +1664 followed by the 7-digit local number. The mobile country code (MCC) for Montserrat is 354.

Do I need to register a sender ID for SMS in Montserrat?

No, alphanumeric sender IDs do not require pre-registration in Montserrat. They are supported with dynamic usage across major networks (Flow and Digicel). However, carriers may modify sender IDs for security purposes. Domestic long codes require 1–2 business days provisioning time.

Which mobile carriers operate in Montserrat?

Two main mobile operators serve Montserrat: Flow (Cable & Wireless, the incumbent operator established pre-2015) and Digicel (entered the market in 2015). Flow maintains broader coverage across inhabited areas, while Digicel offers 4G/LTE services (since late 2017) alongside 2G and 3G networks.

Is two-way SMS supported in Montserrat?

No, major SMS providers do not support two-way SMS in Montserrat according to current specifications. You can send messages to users but cannot receive replies through the same channel.

What are the SMS compliance requirements in Montserrat?

Montserrat SMS compliance requires: (1) Obtaining explicit opt-in consent before sending marketing messages; (2) Supporting HELP/STOP commands (STOP, CANCEL, UNSUBSCRIBE, END, QUIT); (3) Honoring opt-out requests within 24 hours; (4) Maintaining documentation of consent; and (5) Adhering to MICA regulations under the Info-Communications Development Act 2009.

What is the best time to send SMS in Montserrat?

Send SMS in Montserrat between 8:00 AM and 8:00 PM Atlantic Standard Time (AST/UTC-4). Montserrat does not observe daylight saving time. Schedule campaigns during business hours (9:00 AM to 5:00 PM). Avoid sending during major holidays and weekends, and only send outside recommended hours for truly urgent emergency messages.

Can I send concatenated or long SMS messages in Montserrat?

No, concatenated messaging is not supported in Montserrat. Your messages must adhere to standard SMS character limits: 160 characters for GSM-7 encoding and 70 characters for Unicode (UCS-2). Plan your message content to fit within these single-message length limits.

What SMS APIs work with Montserrat?

Several SMS API providers support Montserrat, including Twilio (250 messages/second), Sinch (30 messages/second), MessageBird (60 messages/second), and Plivo (50 messages/second). All providers support alphanumeric sender IDs and E.164 phone number formatting (+1664XXXXXXX).

Does Montserrat support MMS messages?

No, Montserrat does not directly support MMS messages. The system automatically converts MMS messages to SMS with an embedded URL link, ensuring message delivery while providing access to multimedia content through web links. Use short URLs and include clear instructions for accessing the content.

Recap and Additional Resources

Key Takeaways:

• Always format numbers in E.164 format (+1664)
• Implement proper error handling and monitoring
• Follow local compliance requirements
• Test thoroughly before sending bulk messages

Next Steps (Estimated 2–4 weeks for full implementation):

1. Week 1: Review MICA guidelines and implement consent management system (5–7 days)
2. Week 1-2: Set up monitoring infrastructure with webhooks and dashboards (3–5 days)
3. Week 2: Choose and integrate SMS API provider, test with small volumes (2–3 days)
4. Week 3-4: Conduct thorough testing across both carriers, optimize delivery rates (7–10 days)
5. Ongoing: Schedule monthly compliance audits and quarterly review of messaging strategy

Additional Information:

• Montserrat Info-Communications Authority (MICA)
• Government of Montserrat
• UK ICO - International Data Transfers