Update (9 PM UTC):We continue to have traffic issues with our REST API. We'll post updates as they are available, apologies again for the disruption.
Update (5:35 PM UTC):
Since late on the 16th, we have been seeing exceptionally high traffic to our REST API. We have had to block access from two IP ranges served by Amazon Web Services: 52.x.x.x and 34.x.x.x. Please help us and other AWS users by letting us know if this might be you. If you are unable to access our REST API, you use AWS IPs 52.x.x.x or 34.x.x.x, and you increased your activity on Friday, we would love to hear from you so we can find the root of the high traffic. As a public API, we want to provide a fair service to everyone but of course there are limits to our resources and this surge was unexpected. We appreciate your help in resolving this for all other users.