use UI

Mega Menu vs Sidebar & Rail

Both hold a lot of destinations; they differ in whether the navigation is present or summoned. A sidebar is always there, which makes it the right place for the handful of areas someone moves between all day — and it answers “where am I” without any interaction, because the current item is visible. A mega menu is summoned, so it can afford to be large and grouped, and it suits a catalogue people browse rather than a workspace they live in. The tells are permanence and depth: if the same six places are visited constantly, keep them on screen; if forty destinations need grouping and are visited once, open a panel.

A few places used constantly belong in a sidebar. Many places, grouped and browsed occasionally, belong in a mega menu.

Mega Menu

A large panel opened from a nav item, showing many grouped destinations at once.

Reach for it when

  • One nav item leads to twenty or more destinations that group naturally — products by category, docs by section.
  • The groups themselves are useful information: seeing the shape of the catalogue helps people choose.
  • The site is browsed by people who do not yet know what they want.

Avoid it when

  • There are six links. A plain dropdown does it without the layout work or the panel-sized dead zone.
  • The items are actions rather than destinations. Actions in a nav panel are a dropdown menu, and that one really is `role="menu"`.
  • On mobile. A full-width panel over a phone screen is a page — so make it one, or an accordion in a drawer.

Sidebar & Rail

A persistent vertical navigation region beside the main content, optionally collapsed to icons.

Reach for it when

  • The app has a stable set of top-level places people move between all day.
  • The current location needs to stay visible while working — a dashboard, an editor, an admin panel.
  • There is horizontal room to spare, or the layout can afford a rail when there is not.

Avoid it when

  • There are three destinations. A horizontal nav in the header costs nothing and reads faster.
  • The content needs the full width — a document editor, a canvas, a data table with twenty columns.
  • The destinations are marketing pages with deep sub-structure. That is a header nav, possibly a mega menu.