endofmessage

End of message, often abbreviated as EOM or rendered as endofmessage in code, refers to a boundary marker used in computing to indicate that a current message or data block has finished. It is a concept applied across streaming and message-oriented communications to separate individual messages within a continuous flow of data.

End-of-message markers can take different forms. An explicit marker is a fixed sequence of bytes or characters that appears only at the end of a message, such as a protocol-specific delimiter. In text-based protocols, simple markers like a line terminator or a designated token may serve this role. An implicit marker relies on metadata or structure, such as a length field, content-length header, or a framing scheme that indicates message boundaries without inserting a special terminator into the payload.

Common challenges arise when a marker could appear within the message payload. To prevent misinterpretation, protocols often escape such content, use length-based framing, or apply boundaries that are unlikely to occur in normal data. In some classic protocols, end-of-message semantics are tied to specific behaviors, such as a data section terminated by a particular sequence; in modern systems, robust framing frequently favors length-prefixing or chunked encoding over opaque markers.

Applications of end-of-message concepts include network protocols, inter-process communication, messaging queues, and data serialization, where clearly defined boundaries are essential for correct parsing, error handling, and flow control.

See also: delimiter, framing, end-of-data, end-of-transmission.