I'm experiencing random timeouts to some Api endpoints (Fitness, Drupal). all the API endpoints from Google App Engine.
You can check this odd behavior using these links:
http://www.stackprinter.com/topvoted?service=drupal.stackexchange&tagged=&page=3&pagesize=30
http://www.stackprinter.com/topvoted?service=fitness.stackexchange&tagged=&page=3&pagesize=30
http://www.stackprinter.com/topvoted?service=stackoverflow&tagged=&page=3&pagesize=30
All the Stack Exchange app[s] hosted on Google App Engine should be affected by the same problem.
Please star this issue!