Early on Thursday morning Twitter suffered a denial-of-service attack.
As part of their defense against the attack, they blocked a large number IP addresses, including, we presume IP addresses that were making high-volume calls to their API.
TweetLater’s IP addresses were also blocked in the process, since we normally make more than 40 API calls per second in the normal course of our business.
TweetLater was not part of the denial-of-service attack. We were simply caught up as innocent bystanders in Twitter’s defense against the actual attackers.
As part of the recovery from the attack, Twitter is unblocking the white-listed IP addresses of third-party applications such as TweetLater.
This unblocking process is a meticulous one and there are many IP addresses to unblock (not only TweetLater’s).
According to Twitter engineers, the process can last well into Saturday.
We do not know exactly when the actual unblocking of TweetLater’s IP addresses will occur, but we do know they will be unblocked.
We appreciate your patience and understanding.
Normal service will resume as soon as the IP addresses have been unblocked.
Free trials of TweetLater Professional will be extended by a few days once normal service resumes.
Update: This thread on the Twitter Developer Talk Group shows that many other third-party applications were also blocked.
Update Thursday, 8:25 PM EST:
We have now restored normal operations. We have also extended all active free trials of TweetLater Professional by one day.
Update Thursday, 8:38 PM EST: We spoke too soon. Sorry. Services have been paused again. Twitter is not out of the woods yet.
Update Friday, 12:24 PM EST:
Some features of the online website have been restored. All automation processes are still in paused mode, because the Twitter API is still refusing to process any high-volume API requests.
Update Friday, 10:38 PM EST: There has been no change yet. The Twitter API is still refusing to process any type of volume API requests. Twitter has communicated that the denial-of-service attacks have been ongoing and have intensified on Friday, and that they believe those attacks are geopolitical in motivation. Twitter is still defending against the attacks, and has asked everyone to hang in there with them.
Update Saturday, 00:19 AM EST: The latest update from Twitter is that there is no, we repeat, no ETA on when these issues will be resolved.
Update Saturday, 8:12 AM EST: The status has not yet changed. The TweetLater web site is operational, but all Twitter automation is still paused. Blog feeds and Ping.fm automation are processing as usual. Please login to TweetLater and read the service announcement above the blue menu tabs for more details on what is paused and what is running normally.
Update Saturday, 5:44 PM EST: There has been complete and deathly silence from Twitter today. No communication about the status to application developers. We have cautiously turned on the process that publishes scheduled tweets to Twitter. There may be periods where it may be blocked, during which it will revert back to putting tweets that are older than two hours into an error condition. But, so far so good…
Update Saturday, 6:00 PM EST: Nope… As soon as you send even a small volume to the API their edge defenses simply block your IP address. It is high time that Twitter identifies who are their friends, and allow them to operate normally while defending against the bad guys. They already white-list our IP addresses, so they know exactly which IP addresses are approved ones that should be allowed to work normally.
Update Sunday, 10:55 AM EST: The status has not yet changed. All developers of third-party applications are still waiting for an update by Twitter regarding correction of the severe limitations currently imposed by the Twitter API. The last time Twitter has provided any meaningful update was on Friday.
Update Sunday, 1:54 PM EST: The status is still the same. Twitter has published an update saying that the attacks are still ongoing, and that they are still working on restoring normal access to the Twitter API. There still is no timeframe for the resolution of this issue.
Update Sunday, 4:29 PM EST: The Twitter API has now been opened for volume transactions. It appears that the issue has been resolved, and we have resumed normal operations. Existing free trials of TweetLater Professional have been extended by three additional days. Thank you for the patience and support that you have shown.