Domain age is simply the length of time a domain name has been registered, measured from its creation date recorded in WHOIS or RDAP data to the present. It is one of the quickest signals available for judging how established and legitimate a website or business is likely to be.
For sales and lead qualification, domain age adds context to a prospect. A domain registered fifteen years ago suggests a stable, real business, while one created last week warrants more scrutiny - it might be a brand-new startup or a throwaway domain set up for spam. Combined with other signals, age helps prioritize outreach.
In deliverability, domain age intersects with reputation. A freshly registered domain has no sending history, so mailbox providers treat it cautiously; this is why cold-email practitioners often let a new domain sit for a period and warm it up gradually before running campaigns from it, rather than sending high volume immediately.
Domain age also has security implications, since a large share of malicious and phishing domains are very young - registered, used briefly for an attack, and abandoned. Screening lists for suspiciously new domains helps filter out low-quality or risky contacts before you invest effort in them.