Update: We finished early and service is back.
We’ve isolated many different parts of the Twitter system such that they can scale independently. This means a problem with a particular subsystem can be addressed without causing disruption to the service as a whole.
Although we’ve made lots of progress separating these subsystems, not all aspects of Twitter are isolated in this manner. In certain cases, we still need to place the service in maintenance mode to update or improve parts of the overall system.
Our tech team wasn’t able to perform some necessary maintenance strategically planned for a window of time very early Sunday morning where it would affect the least number of folks so we’re doing it right now. For the next hour, Twitter will be placed in maintenance mode.
Thank you for your patience while we hustle to get this work done. We expect the upgrade will take one hour and then the service will be back. Everyone at Twitter uses Twitter so we’re as eager to have it back as you are.