This tutorial teaches developers how to build an auditable SMS proxy using Twilio Programmable SMS, Pangea Audit Service, and JavaScript. The goal is to provide a secure way to record conversations between two parties without exposing the contents of the conversation publicly. By publishing conversation hashes to a blockchain, users can verify that messages were not altered or deleted. The tutorial guides developers through setting up a free Pangea account, configuring their app to communicate with Twilio and Pangea, and deploying the app to a Twilio Serverless environment. Once deployed, the app forwards incoming SMS messages between two configured numbers, logs the conversation on a tamper-proof blockchain, and provides users with verifiable proof of the conversation's integrity. The tutorial concludes by emphasizing the importance of securing communication channels and providing users with a reliable way to verify message integrity.