Building a Fully Serverless Fax Automation System on AWS

Modern businesses require reliable document workflows without the overhead of managing infrastructure. To address this need, we built a fully serverless fax automation system that supports both inbound and outbound fax processing using AWS managed services and Telnyx integration.

The architecture is completely event-driven and eliminates the need for traditional servers or containers. All components are stateless, scalable, and loosely coupled, allowing the system to handle high volumes efficiently while maintaining reliability.

End-to-end serverless fax automation workflow with inbound processing, AI classification, and outbound delivery.

Serverless Architecture Overview

Telnyx handles fax transmission and sends webhook events to Amazon API Gateway, which acts as the public entry point. AWS Lambda processes business logic such as validation, metadata extraction, storage, and status updates. All fax documents are securely stored in Amazon S3, while Amazon SQS manages asynchronous workflows and ensures retry safety. Monitoring and logging are handled through Amazon CloudWatch, and sensitive credentials are stored securely using AWS Secrets Manager.

Inbound and Outbound Fax Processing

For inbound faxes, Telnyx sends a webhook event that triggers a Lambda function. The fax document is stored in S3, and metadata is pushed to SQS for background processing, including AI-based classification and routing.

For outbound workflows, users submit documents through an API. The document is stored in S3, and a Lambda function sends it via the Telnyx Fax API. Delivery status updates are processed asynchronously, ensuring a non-blocking user experience.

Scalability, Security, and Reliability

The system is fully stateless, with workflow coordination handled through SQS. This enables independent scaling of each component and ensures fault isolation. Infrastructure is managed using AWS CloudFormation, with automated CI/CD pipelines powered by GitHub Actions.

Security is enforced using least-privilege IAM roles, secure secret management, and strict input validation. Reliability features include automatic retries, dead-letter queues, and detailed monitoring.

This serverless approach delivers a highly scalable, cost-efficient, and resilient fax automation solution for modern enterprises.