Mailbox, a new mobile mail client for Gmail users on iOS, is now available in the App Store. But before you get overly excited, note that the company is filling reservations on a first come, first serve basis. So unless you signed up in mid-January when the app was unveiled, you’re probably looking at a lengthy wait as the number of sign-ups is pushing 300,000 as of writing.

The app is described as a completely redesigned inbox that makes e-mail feel light, fast and mobile-friendly. Users can quickly swipe messages to send them to an archive or the recycle bin, scan an entire conversation in a chat-like structure or snooze messages until later with the tap of a button. Snoozed messages will return to the inbox automatically so you can focus on what is important at the time.

The company went with the slow rollout system in order to ensure everyone has a fast, reliable e-mail experience. Once the service is deemed stable, they will begin filling requests at a much faster rate until the reservation system is no longer needed.

The free app can be downloaded right now but until your number is called, there’s not a whole lot you can do with it. You can watch the queue in real time, however, which should give you some sort of idea as to how long you’ll have to wait to get in on the action. No word yet on when the app will be available for other platforms.