Domain Authority is a third-party metric from Moz, scored 1 to 100, that estimates how likely a domain is to rank well in search results relative to other domains. It's built primarily from backlink data, quantity, quality, and diversity of the sites linking in, alongside factors like content and domain history.
It's important to be clear about what it isn't: Google doesn't use Domain Authority, doesn't recognize it, and has said explicitly that third-party authority scores play no role in its own ranking algorithm. Its real value is comparative and directional, useful for benchmarking a site against competitors, tracking whether a link-building effort is moving the needle over time, or getting a rough read on how strong a prospective backlink source is before pursuing it. Similar metrics exist from other tools (Ahrefs' Domain Rating, Semrush's Authority Score), and none of them agree exactly, since each is built on a different proprietary formula measuring a similar but not identical idea.
