subaddress

Subaddress is a term used to describe an additional address derived from or associated with a primary address, intended to separate streams of activity, improve organization, or enhance privacy. The exact meaning varies by domain, but the core idea is a secondary address that remains linked to a single overarching identity or account.

In cryptocurrency, subaddresses are most commonly associated with privacy-centric wallets such as Monero. A wallet can generate many subaddresses from the same seed, each with its own public address. Funds sent to a subaddress are still controlled by the same private keys, and the wallet can distinguish incoming payments by subaddress index. Subaddresses allow a user to receive funds to distinct addresses without managing multiple separate wallets, helping to reduce address reuse and make it harder to correlate payments on the blockchain. The use of subaddresses typically does not reveal the main address to the sender, and the wallet owner can choose how many subaddresses to create and monitor.

In email addressing, subaddressing often refers to plus addressing, where a plus sign and an optional tag are added to the local part of an address (for example, [email protected]). This enables automatic filtering and organization by the recipient, allowing messages to be categorized or routed based on the tag. Support for plus addressing varies by service provider; some implement it widely, while others disable or strip the tag for privacy or compatibility reasons.

Beyond these domains, subaddressing generally serves to compartmentalize activity under a single identity or account, providing practical benefits in management and privacy while preserving a common underlying ownership.