originalMessageId

OriginalMessageId is a metadata concept used in messaging systems to store the identifier of the original message from which a derivative item, such as a forwarded copy, an edited version, or an archived replica, originates. The value helps preserve provenance, support threading, and assist in deduplication and auditing across mail stores and messaging platforms.

In email, each message is typically identified by a Message-ID header. Some gateways, archivers, or clients also attach an Original-Message-ID (or OriginalMessageId) header to copies or forwards to record the segment of the conversation back to its source. The exact header name and placement can vary between implementations.

In API models and data stores, originalMessageId is often represented as a string field that references another record, either within the same system or in an external system. It may correspond to a UUID, a Message-ID, or another unique identifier used by the producer of the original message.

Usage implications include privacy and data governance considerations, since propagating original identifiers can reveal message lineage across domains. Some systems preserve the original identifier for all derived items, while others limit or obfuscate it when exporting or sharing data.

See also: Message-ID, In-Reply-To, threading, provenance.