Toast
A brief message about something that just happened, in the bottom-right corner.
Default
One sentence in sentence case, with no trailing period. Confirm a completion as the noun and what happened to it, like “Domain added”, never “successfully”. Toasts stack in the bottom-right corner: the newest sits in front and the stack expands on hover. The region announces politely to screen readers.
Variants
Success, warning, and error fill the toast with blue, amber, and red. An error is two sentences that end with a recovery step, like “Couldn’t verify domain. Try again.”
Undo
An action goes on the right, beside the dismiss button. Prefer an undo toast to a confirmation dialog for anything reversible; it stays up for 8 seconds so there is time to reach it.