How to build international two-way SMS with Amazon Connect Customer, Part 1

This article explains how to build international two-way SMS with Amazon Connect Customer using AWS End User Messaging, covering the architecture, country-specific requirements, and registration processes needed for global SMS support.

• Four-layer architecture: agent workspace (Amazon Connect), messaging integration (SNS/SQS/Lambda/DynamoDB), delivery (AWS End User Messaging), and compliance (country registrations)
• Inbound SMS flows from customer through EUM to SNS, triggering Lambda to create or reconnect chat sessions in DynamoDB
• Outbound messages stream from Connect through SNS/SQS to Lambda, which routes through ITFN (US/Canada) or international phone pools
• Phone pools group origination identities by country; EUM automatically selects the correct identity based on destination
• Sender IDs are outbound-only; pair with short codes or long codes for two-way capability in countries like India and UAE
• Short code registration takes 8-12 weeks; plan registrations during design phase, not implementation
• Use TRANSACTIONAL message type for agent conversations; cannot be changed after pool creation
• Session state stored in DynamoDB links customer phone numbers to active Connect chat sessions for message routing

Part 1 covers the architecture and design considerations; Part 2 will provide implementation details, Lambda functions, and deployment steps for the multi-country SMS solution.