chasquid

chasquid is an open source SMTP server for sending and receiving email through the standard email transfer protocol. Its design focuses on simplicity, security, and ease of operation. It is intended for people or organizations that need to run an email server and prefer software centered on those priorities. No specific paid product is identified as a direct replacement for chasquid, so it should not be presented as an equivalent to any particular commercial email server. The available information also does not describe its feature set beyond SMTP service or claim compatibility with the administration tools, integrations, support services, or other capabilities of a paid product. Its clearest distinction is therefore its stated focus: providing an SMTP email server that emphasizes simple, secure, and straightforward operation.