Link building
Link building is the practice of getting other websites to link to yours, because search engines treat a link from one site to another as a signal that the destination is worth showing to searchers.
Also called: backlink building, off-page SEO
Last reviewed
It is the main lever of off-page SEO - the part of ranking that happens on other people's websites rather than your own. On-page work (titles, content, internal structure, site speed) is entirely within your control; links are not, which is exactly why they carry weight as a signal and why they are the harder half of the job.
In practice, link building is mostly outreach and relationship work rather than technical work. You identify sites whose audience overlaps yours, find the person who decides what gets published, and give them a genuine reason to link - a resource worth citing, an article worth running, a quote worth including. The research and the follow-up consume most of the hours; the actual writing is a small fraction.
The term covers a wide quality range, from earning a citation in a trade publication to buying a link on a site that exists only to sell links. Those sit at opposite ends of what search engines want, and the difference is the single most consequential decision in a link-building program.
Common questions
Does link building still work?
Yes - links remain one of the signals search engines use to rank pages, and Google has never said otherwise. What has changed is the tolerance for low-quality links: tactics that manufacture links at scale are explicitly against Google's spam policies and are increasingly ineffective, while editorially earned links continue to matter.
How long does link building take to affect rankings?
There is no fixed timeline. A link has to be crawled and indexed before it can count at all, which takes days to weeks, and its effect on rankings is gradual and mixed in with every other ranking factor. Anyone quoting you a specific timeline or ranking outcome is guessing.