On top of public-facing enhancements
, Apple has made a variety of developer-side improvements for iOS 8. The new iOS SDK includes over 4,000 APIs, and features like Extensibility, which permit apps to extend services and functions to other apps. Extensions are still sandboxed, but link software using a secure framework.
Some given examples of the possibilities include photo editing tools, Pinterest support, and Bing translation. Apple is also enabling third-party keyboards for the first time, which unlike iOS 8's native QuickType can be granted Internet access.
Touch ID fingerprint security can now be used by third-party apps and Keychain, instead of just for unlocking a phone or making iTunes purchases. Apple is promising that as in iOS 7, fingerprints will be stored on-device and never shared with third parties.
Other new frameworks include HomeKit home automation standards, and CloudKit, which is intended to simplify cloud-related backends. The technology is described as "free with limits," including a default of 1PB of assets, a 10TB database, 5TB/day asset transfer, and 50GB/day database transfer.
For 3D-based apps Apple has introduced Metal, a new platform intended to speed up graphics by reducing OpenGL overhead. The result is more polygons on-screen and rendering effects that would normally be reserved for consoles and PCs. Likewise Apple has improved its SpriteKit 2D graphics technology with support for things like light sources, per-pixel physics, and inverse kinematics. SceneKit is a new 3D scene renderer based on SpriteKit, with things like physics and scripted actions.