Bitly recently released their version 3 API. From this 0.5.0 release, the gem will continue to work the same but also provide a V3 module, using the version 3 API. The standard module will become deprecated, as Bitly do not plan to keep the version 2 API around forever. Then, when you call Bitly.new(username, api_key) you will get a Bitly::V3::Client instead, which provides the version 3 api calls (shorten, expand, clicks, validate and bitly_pro_domain). See http://dev.bitly.com for details.