STunnel is a robust tool designed to provide secure encrypted connections for client-server applications through an SSL/TLS tunnel. Its primary purpose is to encrypt the data transfers of various services like POP3, SMTP, and HTTP, thus enhancing security even when the underlying protocols do not support encryption natively. By wrapping data connections in SSL, STunnel helps protect against eavesdropping and ensure data integrity across the internet or other untrusted networks.The software is versatile, running on multiple platforms such as Windows, Linux, and macOS, ensuring broad compatibility and deployment flexibility. It is widely used in securing database connections, email services, and accessing APIs over the internet.