Esteban Herrera, a seasoned software developer with over twelve years of experience, shares a detailed tutorial on creating a web application that verifies file existence using time-stamped transactions in the Bitcoin blockchain. The application utilizes Node.js, Tierion, RethinkDB, PubNub, and jsreport-core to store file hashes in Bitcoin's Blockchain, enabling users to certify a file's existence at a specific time without revealing its contents. The decentralized nature of blockchain ensures data integrity and anonymity, eliminating the need for central authority verification. The tutorial explains the setup process, from creating the project directories and dependencies to configuring the server-side code. It highlights using Tierion's Hash API for blockchain transactions and RethinkDB's changefeed for real-time updates, while PubNub's Storage and Playback feature ensures data synchronization. Through this application, users can upload files, generate SHA256 digests, and receive blockchain receipts, which can be checked on platforms like Block Explorer or Blockchain.info. The tutorial also covers the verification process using Merkle Trees and Tierion's validation tools, demonstrating how blockchain technology can be leveraged for secure and efficient data certification.