The author, Ricky Robinett, shares his experience building a digital decoder ring using PHP, FilePreviews.io, and Twilio MMS. The application allows users to send an image of a Caesar ciphered text via MMS, which is then analyzed by FilePreviews' OCR API. The decoded text is sent back as a response, where the user can see the decoded message displayed on their phone screen. To achieve this, the author uses Twilio's PHP helper library to handle incoming messages and generate TwiML responses. Additionally, they use Firebase's JWT library to parse the JSON Web Token sent by FilePreviews, allowing them to access the OCR results. With these tools, users can now build their own digital decoder ring apps to decode Caesar ciphers using MMS and PHP.