Tapbots has released the first beta of Tweetbot for Mac, an important milestone that moves the popular OS X Twitter client closer to an official public release. The latest version includes a number of bug fixes and performance optimizations, but you'll only be able to use the app if your account was authorized for previous alpha builds; Twitter's restrictive new APIs continue to prevent new users from partaking in the beta, and existing users won't be able to add or delete accounts with the client at this stage.

Tapbots' cautious approach is the direct result of Twitter's much-maligned new APIs and guidelines for third-party apps, which have forced developers to conserve "tokens" that cap the total number of users at 100,000. Revoking an app's access to Twitter will return such tokens to the pool, but it seems that's not enough consolation for Tapbots, which wants to save those slots for the final (paid) Mac App Store release. There's no ETA for when we can expect to see Tweetbot 1.0, but the rapid pace of development has us hoping it won't be a long wait. For the full changelog of what you'll see in the beta, follow the source below to the Tapbots blog.