Twitter is recovering from an unspecified technical problem that affected the microblogging service's main site and its APIs (application programming interfaces) for about one hour late Tuesday morning. Twitter is almost done fixing the issue but the service hasn't fully returned to normal availability levels yet, the company said in its official Twitter Status blog.

"We had a system-side issue this morning starting around [11 am US Eastern Time] that resulted in Twitter.com experiencing two 30 minute back-to-back incidents over roughly one hour," the note reads.

Prior to the problems on Tuesday, Twitter had been having a solid month of June with only two minutes of downtime, according to web performance monitoring company Pingdom.

Twitter logged 52 minutes of downtime last month, for a 99.88 percent uptime rate, and was better in April when it was down for 37 minutes, according to Pingdom.

Attention to Twitter's availability and performance issues increases along with the service's booming global popularity as the preferred tool for individuals, celebrities and companies to communicate with a massive audience via short text status updates. In February, Twitter said that its users post 50 million tweets per day, or an average of 600 per second.

The company was once notorious for its frequent and extended outages but has improved significantly, although it still slips. For example, in August of last year it had more than six hours of downtime and in October more than five hours. Its worst month so far this year was January with 89 minutes of downtime, according to Pingdom.