Puerto Rico (US) SMS Best Practices, Compliance, and Features

Puerto Rico (US) SMS Market Overview

Market Conditions: Puerto Rico's mobile market is closely integrated with the US telecommunications ecosystem, with major US carriers like T-Mobile and AT&T providing local service alongside regional operators. SMS remains a primary communication channel for business messaging, with high mobile penetration rates. WhatsApp and other OTT messaging apps are popular for personal communication, but SMS is preferred for business and verification messages due to its reliability and universal reach.

Key SMS Features and Capabilities in Puerto Rico (US)

Puerto Rico supports comprehensive SMS capabilities including two-way messaging, with features and regulations aligned with US mainland standards.

Two-way SMS Support

Two-way SMS is fully supported in Puerto Rico, allowing businesses to engage in interactive messaging with customers. No special restrictions apply beyond standard US messaging regulations and carrier requirements.

Concatenated Messages (Segmented SMS)

Support: Concatenated messaging is not supported through the Sent.dm platform for Puerto Rico.
Message length rules: Messages follow standard SMS character limits - 160 characters for GSM-7 encoding and 70 characters for Unicode (UCS-2).
Encoding considerations: Both GSM-7 and UCS-2 encodings are supported, with GSM-7 recommended for standard ASCII characters to maximize message length.

MMS Support

MMS messages are automatically converted to SMS with an embedded URL link to the media content. This ensures reliable delivery while still allowing businesses to share rich media content with recipients.

Recipient Phone Number Compatibility

Number Portability

Number portability is not available in Puerto Rico. This means phone numbers remain tied to their original carriers, which can help ensure more reliable message routing.

Sending SMS to Landlines

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

Compliance and Regulatory Guidelines for SMS in Puerto Rico (US)

As a US territory, Puerto Rico follows US federal telecommunications regulations, including TCPA (Telephone Consumer Protection Act) and CTIA guidelines. Businesses must comply with both federal requirements and carrier-specific rules for A2P messaging.

Consent and Opt-In

Explicit consent is mandatory before sending any marketing or promotional messages. Best practices include:

• Collecting written or digital consent with clear terms
• Maintaining detailed records of opt-in dates and methods
• Specifying message frequency and content type
• Using double opt-in for marketing programs
• Providing clear disclosure of message and data rates

HELP/STOP and Other Commands

• Required Keywords: Must support standard STOP, QUIT, CANCEL, UNSUBSCRIBE, and HELP commands
• Language Support: Commands must be recognized in both English and Spanish
• Response Time: Acknowledge opt-out requests within 24 hours
• Help Messages: Must include program information, support contact, and message frequency

Do Not Call / Do Not Disturb Registries

Puerto Rico follows the US National Do Not Call Registry. Best practices include:

• Regularly scrubbing contact lists against the National DNC Registry
• Maintaining internal do-not-contact lists
• Implementing immediate opt-out processing
• Documenting all opt-out requests and processing dates

Time Zone Sensitivity

Puerto Rico observes Atlantic Standard Time (AST). Recommended messaging hours:

• Standard Business Hours: 8:00 AM - 8:00 PM AST
• Emergency Messages: Allowed 24/7 for critical notifications
• Marketing Messages: Restrict to business hours only
• Consider Holidays: Respect local holidays and cultural observances

Phone Numbers Options and SMS Sender Types for in Puerto Rico (US)

Alphanumeric Sender ID

Operator network capability: Not supported for dynamic usage
Registration requirements: Not applicable
Sender ID preservation: Not preserved - messages will display numeric sender ID

Long Codes

Domestic vs. International:

• Domestic long codes supported with required 10DLC registration
• International long codes not supported

Sender ID preservation: Yes, for registered 10DLC numbers
Provisioning time: 1-3 business days for 10DLC registration
Use cases:

• Two-factor authentication
• Appointment reminders
• Customer service
• Transactional messages

Short Codes

Support: US short codes supported by major carriers
Provisioning time: 8-12 weeks for new short code approval
Use cases:

• High-volume marketing campaigns
• Time-sensitive alerts
• Mass notifications
• Promotional campaigns

Restricted SMS Content, Industries, and Use Cases

Prohibited Content:

• Gambling and lottery services
• Adult content or SHAFT (Sex, Hate, Alcohol, Firearms, Tobacco)
• Cryptocurrency promotions
• Debt collection
• Political messaging without proper disclosure

Content Filtering

Carrier Filtering Rules:

• Messages containing prohibited keywords are blocked
• URLs must be from approved domains
• High-frequency messaging may trigger spam filters

Best Practices to Avoid Filtering:

• Avoid URL shorteners
• Use registered domains
• Maintain consistent sending patterns
• Include clear business identification
• Avoid excessive punctuation and all-caps

Best Practices for Sending SMS in Puerto Rico (US)

Messaging Strategy

• Keep messages under 160 characters when possible
• Include clear call-to-actions
• Use personalization tokens thoughtfully
• Maintain consistent sender identification

Sending Frequency and Timing

• Limit marketing messages to 2-4 per month per recipient
• Respect quiet hours (8 PM - 8 AM AST)
• Avoid sending during major holidays
• Space out bulk campaigns to prevent network congestion

Localization

• Offer messages in both Spanish and English
• Consider cultural context and local preferences
• Use appropriate date and time formats
• Include local contact information when possible

Opt-Out Management

• Process opt-outs in real-time
• Maintain centralized opt-out database
• Confirm opt-outs with acknowledgment message
• Regular audit of opt-out list compliance

Testing and Monitoring

• Test across major carriers (AT&T, T-Mobile, local operators)
• Monitor delivery rates by carrier
• Track opt-out rates and patterns
• Regular testing of opt-out functionality
• Monitor for carrier filtering changes

SMS API integrations for Puerto Rico (US)

Twilio

Twilio provides a robust SMS API with comprehensive support for Puerto Rico messaging. Integration requires your Account SID and Auth Token from the Twilio Console.

import { Twilio } from 'twilio';

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

// Function to send SMS to Puerto Rico
async function sendSMSToPuertoRico(
  to: string,
  message: string
): Promise<void&gt; {
  try {
    // Ensure number is in E.164 format for Puerto Rico (+1787XXXXXXX or +1939XXXXXXX)
    const formattedNumber = to.startsWith('+1') ? to : `+1${to}`;
    
    const response = await client.messages.create({
      body: message,
      to: formattedNumber,
      from: process.env.TWILIO_PHONE_NUMBER, // Your registered 10DLC or shortcode
      statusCallback: 'https://your-webhook.com/status', // Optional delivery status updates
    });
    
    console.log(`Message sent successfully! SID: ${response.sid}`);
  } catch (error) {
    console.error('Error sending message:', error);
    throw error;
  }
}

Sinch

Sinch offers SMS capabilities through their REST API, requiring an API Token and Service Plan ID.

import axios from 'axios';

class SinchSMSService {
  private readonly apiToken: string;
  private readonly servicePlanId: string;
  private readonly baseUrl: string = 'https://us.sms.api.sinch.com/xms/v1';

  constructor(apiToken: string, servicePlanId: string) {
    this.apiToken = apiToken;
    this.servicePlanId = servicePlanId;
  }

  async sendSMS(to: string, message: string): Promise<void&gt; {
    try {
      const response = await axios.post(
        `${this.baseUrl}/${this.servicePlanId}/batches`,
        {
          from: process.env.SINCH_SENDER_ID,
          to: [to],
          body: message
        },
        {
          headers: {
            'Content-Type': 'application/json',
            Authorization: `Bearer ${this.apiToken}`
          }
        }
      );
      
      console.log('Message sent successfully:', response.data.id);
    } catch (error) {
      console.error('Failed to send message:', error);
      throw error;
    }
  }
}

MessageBird

MessageBird provides SMS API access with straightforward integration options.

import { MessageBird } from 'messagebird';

class MessageBirdService {
  private client: MessageBird;

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

  async sendSMS(to: string, message: string): Promise<void&gt; {
    const params = {
      originator: process.env.MESSAGEBIRD_SENDER_ID,
      recipients: [to],
      body: message,
      reportUrl: 'https://your-webhook.com/delivery-reports'
    };

    return new Promise((resolve, reject) =&gt; {
      this.client.messages.create(params, (err, response) =&gt; {
        if (err) {
          console.error('Error sending message:', err);
          reject(err);
        } else {
          console.log('Message sent successfully:', response.id);
          resolve();
        }
      });
    });
  }
}

Plivo

Plivo's SMS API provides reliable message delivery to Puerto Rico with detailed delivery tracking.

import plivo from 'plivo';

class PlivoSMSService {
  private client: plivo.Client;

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

  async sendSMS(to: string, message: string): Promise<void&gt; {
    try {
      const response = await this.client.messages.create({
        src: process.env.PLIVO_SOURCE_NUMBER, // Your Plivo number
        dst: to,
        text: message,
        url: 'https://your-webhook.com/delivery-status'
      });
      
      console.log('Message sent successfully:', response.messageUuid);
    } catch (error) {
      console.error('Failed to send message:', error);
      throw error;
    }
  }
}

API Rate Limits and Throughput

• Standard Rate Limits:
  • 10DLC: 1-2 messages per second
  • Short codes: Up to 100 messages per second
  • Toll-free numbers: 3 messages per second

Throughput Management Strategies:

• Implement exponential backoff for retries
• Use message queuing systems (Redis, RabbitMQ)
• Batch messages for optimal throughput
• Monitor carrier feedback for delivery optimization

Error Handling and Reporting

• Implement comprehensive error logging
• Monitor delivery receipts via webhooks
• Track common error codes and responses
• Set up alerts for unusual error rates
• Maintain delivery status dashboard

Recap and Additional Resources

Key Takeaways

1. Compliance First:

   • Register for 10DLC if using long codes
   • Maintain proper consent records
   • Honor opt-out requests immediately

2. Technical Best Practices:

   • Use E.164 number formatting
   • Implement proper error handling
   • Monitor delivery rates

3. Localization Considerations:

   • Support both English and Spanish
   • Respect local time zones
   • Consider cultural context

Next Steps

1. Review TCPA and CTIA guidelines
2. Register for 10DLC if not already done
3. Set up delivery monitoring systems
4. Test message delivery across carriers

Additional Information:

• FCC Guidelines
• CTIA Messaging Principles
• The Campaign Registry
• Puerto Rico Telecommunications Bureau