HS SMTP LITE is a software library in C (supplied with full source code) which implements the client side of Simple Mail Transfer Protocol (SMTP) over TCP socket layer according to RFC 821.

Support for transfer of basic message header and text is providedFrom version 1.1, HS SMTP LITE supports ESMTP extension for LOGIN Authentication using Base64 encoding and message sending to multiple recipients from address list.From version 1.2 HS SMTP LITE supports sending binary file attachments using MIME version 1.0 base64 encodingTo send a text email message to any address on the internet, the user application calls a single function HsSmtpSendMail, specifying mail server name or IP address, sender address, recipient address, message text buffer and length, subject, cc and an event callback function to use for reporting of operation result and server errors.HS SMTP library then resolves the server name, connects to it and transmits the message according to SMTP RFC 821 protocol.

HS SMTP Library incorporates the necessary state machine, transparency procedures, and server response processing required to comply to a simple and robust SMTP client implementation.Modular design makes it easy to port HS SMTP protocol module to any environment.

HS SMTP internally at a lower layer interfaces to HS Sock library which provides TCP transport services.