The Wayback Machine's API only supports finding the archive with the closest date match, not strictly one in the past. By using the Memento API however, we can ask for the closest match and, if it is in the future, get the previous match.
The simplest way to add support for this is a "Strict Mode" checkbox when using the Wayback Machine that will always get a match in the past. It is possible for the closest match to be a few days in the future, and the previous match to be years in the past, so there's still a use case for wanting closest.
The Wayback Machine's API only supports finding the archive with the closest date match, not strictly one in the past. By using the Memento API however, we can ask for the closest match and, if it is in the future, get the previous match.
The simplest way to add support for this is a "Strict Mode" checkbox when using the Wayback Machine that will always get a match in the past. It is possible for the closest match to be a few days in the future, and the previous match to be years in the past, so there's still a use case for wanting closest.