A message to users confirming their edit was successful.
A/B testing by the editor engagement experiments team compared delivering a confirmation post-save to a control group and a group which received a message of thanks for editing. This first round of post-edit feedback testing showed that a simple, unobtrusive confirmation message, "your edit was saved", led to a significant increase in the ability of new Wikipedia editors to contribute, without sacrificing quality.
Based on those results, and the fact that confirmation messages are a standard usability pattern, we're building a confirmation message into current MediaWiki editing. We're also recommending that a confirmation be included in the VisualEditor. (bug 39632)
User experience 
The following requirements match the successful version A/B tested on English Wikipedia. Requirements and design for VisualEditor may vary in order be consistent with that project's design.
- A confirmation message declaring "Your edit was saved." will be displayed to users every time they successfully save all edits, and the page is reloaded in read mode. Since this enhancement was tested with new editors and may be an annoyance to those who expect no confirmation other than page reload, this feature will only be enabled for new or anonymous editors.
- The message will appear in a modal that is overlaid on the page, so that it will be visible even if the user is returned to a section via an anchor in the link.
- The message will fade away after approximately three seconds.
- The message will be dismissible by the user.
Alternative designs 
The following ideas (please expand if you like!) are options for future improvements to test. They have not been priortized, but should be documented so we don't lose them.
- Confirmation immediately after save/before page reload
- Instead of delivering the confirmation after page reload, one idea to test is providing confirmation after successful submit, stalling the page reload function to let people decide to view or edit. The goal of this version would be to create a greater affordance for follow up editing (See mockup). We haven't explored the technical challenges of this approach yet, so keep that in mind.
- Other designs for confirmation modals
- Munaf Assaf, UX designer on the E3 team, produced a wide variety of options we considered (See gallery below). Ultimately we went with the fairly standard and international option of a green checkmark, but a future design review may bring up new needs in the context of icon standardization.
Technical documentation 
Normally a single notification like this would be built into core, like the current watchlist notification. However, since we want to enable this feature only for new users and do some consistent restyling of the bubble notification system, this is not necessarily the best solution. Thus, we've built this into Extension:PostEdit.
Future versions of this may build upon the
mw.notify method (aka "bubble notifications"), with some enhancements either directly or in custom styling. See bug 40307 for a list of proposed design changes overall, including some blockers for meeting usability requirements.