A flat file API is a type of integration technology which allows for the transfer of data stored in plain text files from one system to another. By using this type of API, businesses can easily accept, send, and move data between different systems with ease and efficiency. Flat file APIs simplify the process of exchanging data without complex formatting or encoding that is typically required for database connectivity. The flat file transfer format is often used for quick data backups, online payments, and digital transactions. By utilizing flat file APIs, companies can affordably and securely exchange data between systems with ease and accuracy.