The VKontakte Swift SDK by SwiftyVK allows developers to access the VKontakte API from their iOS and macOS applications written in Swift. This SDK requires Swift 4.0+, iOS 8.0+, macOS 10.10+, and Xcode 9.0+.
Gowalla, Foursquare, Yelp, Facebook Places, the list goes on. There's certainly no shortage of methods to tell people where you are and what you're doing while you're there. Startup Whatser, built on the SoGeo API for location-based apps, has jumped into the ring with a different approach to check-in services: to be useful.
Hipmob is an easy-to-use mobile chat client that works to connect customers with customer service and support, in real time. It's a simple process of integrating the Hipmob library into the Android or iPhone app, then logging in to any Jabber or XMPP enabled IM client.
Geeklist offers developers an online haven to present their work, connect with other developers, and gain credit for achievements. Geeklist's lean staff proudly states that Geeklist was "[b]uilt by developers, for developers... we make geeks lives better every day." The API allows developers to create their own applications and services and retrieve any needed data from the Geeklist database. The API has remained in private beta since the Geeklist's original launch, but will open to the public with a 48-hour hackathon from November 30 - December 3.