The Fax Gateway is an open-source system built on top of the Twilio API to send faxes reliably, particularly in states where email is not accepted or counties are overwhelmed with email submissions. The system uses Amazon SQS and AWS Lambda to handle queuing, retrying, and processing faxes. It includes features such as message grouping, deduplication, and delay queues to prevent overloading of fax machines and ensure successful delivery of faxes. The system also handles failed faxes by writing them to a retry queue, where they are re-sent after a delay, and provides webhooks for notification back to the application that sent the fax. The Fax Gateway can be easily deployed in an AWS account using the Serverless Framework and is customizable to fit specific use cases.