As many of you have recently noticed, something has gone a bit wrong with the GW2 API system over the past weekend. We had a server fail which was responsible for tracking what sorts of content should be visible via the API. This server watches the game and every time someone picks up an item, unlocks an achievement, plays an event, and so on, it records the ID number of the content and adds it to a whitelist. The whitelist in turn controls what data we show via the API.
The reason for this mechanism is to avoid spoiling content that has not been found by players naturally. The whitelist allows us to safely show data on things players have found in the game, but keep a few things under wraps if they haven't been experienced by anyone yet. Essentially it keeps the API from leaking spoilers for new content.
I mentioned above that the server responsible for this whitelist had a failure. The bottom line is that the whitelist was effectively reset, and every discoverable piece of content in the game has to be re-experienced in order to add it back to the whitelist. Much of the game's data is already visible again, but a chunk of it will be hidden until players come across it in-game one more time.
We are of course trying to restore the whitelist data from backups and other measures. I wanted to share our current status in case those other measures don't pan out.
We're also tracking a number of other issues with the API, including map data availability, intermittent failures of different sorts, and various endpoints being inoperable. These issues are unrelated to this weekend's failure and will be addressed separately.