Global navigation

Global navigation is the set of destinations reachable from every screen, and local navigation is the set scoped to the section the reader is already in. That one sentence is the whole distinction, and it is worth memorising because the two are constantly built as though they were the same control. Global navigation is identical on the account page and on the search results page. If a link appears in it on some pages and not others, it is not global, whatever it is docked to.

The constraint that gives the pattern its shape is that the list has to be short enough to stay whole. Whatever is in global navigation is in it forever, on every page, in a strip that also has to hold a brand mark and an account control, so every addition costs the same few pixels on every screen in the product. Seven items is the usual practical ceiling and five is more comfortable. This is why the top tier of a site’s structure and its global navigation are not automatically the same list: the structure can be as wide as it needs to be, and the navigation is an editorial selection from it, which is the distinction NN/g draws between information architecture and navigation.

Its physical form varies more than its job does. On the web it is usually a navigation bar across the top; on a phone it is a bottom navigation bar, on a tablet a navigation rail, and on a wide desktop app a sidebar, which is one reason adaptive layout treats it as the thing that changes shape at every size class. Collapsing it behind a hamburger menu is the most consequential version of that change, because a global nav that is hidden by default stops advertising what the product contains. Where the list is genuinely large, a mega menu is the honest way to show a second tier without pretending it fits in a strip.

Two things it must always carry. A current page indicator, so the bar answers “where am I” and not only “where can I go”: without it a reader has to infer their location from the page content, every time. And a landmark role, since a navigation region announced as such is what lets a screen reader user jump straight to it, and is the anchor a skip link exists to skip past. What it does not have to carry is depth. Trailing a reader’s path back up through the hierarchy is breadcrumbs’ work, and the site footer is where the long, complete, unedited list of everything belongs.