Undo
Reversing the last action, which is the single highest-value safety mechanism in most products.
Definition
Undo reverses a completed action, restoring the previous state. It replaces most confirmation dialogs and makes exploration safe, which changes how willing users are to learn by trying.
Expert heuristic. A review criterion developed by practitioners. Useful and widely taught, but evaluated by judgement rather than measurement.
Implementation decisions that matter
- Scope: is undo global, per document, or per surface? Users expect it to reverse the last thing they did, whatever that was.
- Duration: long enough to notice the mistake. A four-second toast is not long enough for most people.
- Reachability: the keyboard shortcut, a menu entry and an inline control, not only a transient message.
- Depth: multiple levels where feasible, and a clear statement of the limit where not.
- Collaboration: in shared documents, undo should reverse your own action, not someone else's.
In practice
Undo instead of confirm
Mail and task toolsSend with a short undo window replaced the confirm-before-send dialog and is now the expected behaviour. Nobody is interrupted, and the mistake is still recoverable.
Continue from here
Each link says what the connection is, so you can tell a principle from an alternative from a thing people mix this up with.
Applies when you are designing
Principles behind this
The reasoning this solution is an application of.
- Error PreventionHeuristic
- User Control and FreedomHeuristic
- ForgivenessPrinciple
Often used with
These usually appear in the same screen or the same decision.
- ToastComponent
- CollaborationPattern
- Destructive ActionsPattern
Alternative approach
A different answer to the same problem, with a different cost.
- ConfirmationPattern
Undo costs nothing when the user was right. Confirmation taxes every action to catch the rare mistake.
Related concept
Connected closely enough to change how you apply this.
- Confirmation and Destructive CopyUX writing