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Building AI-Powered SMS Responses with AWS End User Messaging

Learn how to create an automated SMS response system using AWS short codes, End User Messaging, Lambda, and Bedrock to deliver intelligent AI responses to customer inquiries

Anonymous User
Amazon Employee
Published May 15, 2025

Introduction

In today's fast-paced digital world, customers expect quick, accurate responses to their inquiries across multiple channels. Text messaging remains one of the most direct and effective communication methods, with open rates exceeding 98%. This article provides a comprehensive guide to building an intelligent SMS response system using Amazon End User Messaging, SNS, Lambda, and Amazon Bedrock to automatically respond to customer inquiries via short code.

Understanding the Architecture

Our solution leverages several AWS services to create a seamless, automated messaging experience:
This architecture provides:
  • Immediate response to customer inquiries
  • Natural language understanding and generation
  • Scalability to handle varying message volumes
  • Detailed analytics on customer interactions

Implementation Guide

Step 1: Acquiring and Setting Up Your Short Code

Short codes are 5-6 digit numbers that enable high-volume SMS messaging with consistent sender identity:
1. Application Process:
  • Apply through AWS for a dedicated short code
  • Complete the carrier registration process with your use case details
  • Prepare for an 8-12 week approval timeline
2. Cost Considerations:
  • Short code lease: ~$1,000/month (industry standard fee)
  • AWS provisioning fee: ~$995/month
  • One-time setup fee: ~$650
3. Configuration in AWS:

Step 2: Setting Up the Message Processing Pipeline

Configure SNS Notification System

Create the Lambda Function

The Lambda function serves as the brain of our operation, processing incoming messages and generating responses:

Connect SNS to Lambda

Step 3: Configuring Amazon Bedrock

Amazon Bedrock provides the AI capabilities that power our intelligent responses:
1. Model Selection:
  • • Claude models excel at nuanced understanding and natural responses
  • • Titan models offer good performance at lower cost
  • • Llama 2 provides another strong option for text generation
2. IAM Permissions:
3. Prompt Engineering:
  • Include system instructions to keep responses SMS-friendly
  • Provide context about your business to improve response quality
  • Set appropriate temperature and token limits

Step 4: Testing and Optimization

Before full deployment, thoroughly test your system:
1. End-to-End Testing:
  • • Send test messages to your short code
  • • Verify response quality and timing
  • • Test edge cases and common customer queries
2. Response Optimization:
  • • Analyze response quality and adjust prompts
  • • Fine-tune message length for SMS constraints
  • • Create specialized handling for common queries
3. Performance Monitoring:

Advanced Features and Enhancements

Implementing Conversation Memory

For more context-aware responses, implement conversation memory:

Integrating with Business Systems

Connect your SMS system to business data sources:

Implementing Analytics

Track system performance and customer satisfaction:

Cost Analysis and Optimization

Understanding the costs helps optimize your implementation:
1. Fixed Costs:
  • Short code lease: ~$1,000/month
  • AWS provisioning: ~$995/month
2. Variable Costs:
  • SMS messages: $0.00645 per outbound message segment in the US
  • Lambda: ~$0.20/million invocations + compute time
  • SNS: $0.50 per million notifications
  • Bedrock: Varies by model (Claude v2: ~$8.00 per million input tokens, $24.00 per million output tokens)
3. Cost Optimization Strategies:
  • Use message batching for high-volume scenarios
  • Implement caching for common queries
  • Consider switching to long codes for lower volumes
  • Optimize Bedrock prompts to reduce token usage

Best Practices and Compliance

Messaging Compliance

1. Opt-in/Opt-out Management:
  • Always honor STOP requests (handled automatically by End User Messaging)
  • Include clear opt-out instructions in initial messages
  • Maintain records of customer consent
2. Message Content Guidelines:
  • • Identify your business in each message
  • • Avoid sending during late night hours
  • • Ensure content complies with TCPA and carrier requirements

Security Considerations

1. Data Protection:
  • Encrypt sensitive data at rest and in transit
  • Implement least privilege IAM policies
  • Consider phone number hashing for analytics
2. Input Validation:
  • Sanitize all incoming messages
  • Implement rate limiting to prevent abuse
  • Monitor for unusual patterns or potential attacks

Real-World Use Cases

This solution enables several powerful business applications:
  1. Customer Support: Answer common questions instantly
  2. Order Status Updates: Allow customers to check order status via text
  3. Appointment Management: Confirm or reschedule appointments
  4. Product Information: Provide details about products or services
  5. Feedback Collection: Gather customer feedback through conversational AI

Conclusion

Building an AI-powered SMS response system with Amazon End User Messaging and Bedrock creates a powerful channel for customer engagement. By combining the ubiquity of text messaging with the intelligence of generative AI, businesses can provide instant, accurate responses to customer inquiries at scale.
This solution not only improves customer satisfaction through faster response times but also reduces the operational burden on support teams by handling routine inquiries automatically. As AI capabilities continue to evolve, the potential applications for this technology will only expand.
Have you implemented AI-powered messaging in your business? Share your experiences and insights in the comments below!
 

Any opinions in this post are those of the individual author and may not reflect the opinions of AWS.

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