A library that creates status bar notifications.

The Firebase iOS framework for adding realtime data synchronization to your app.

A collection of source from different Google projects that may be of use to developers working other iOS or OS X projects.

Nanopb - protocol buffers with small code size

Protocol Buffers (a.k.a., protobuf) are Google's language-neutral, platform-neutral, extensible mechanism for serializing structured data.

StoreKit enables users to embed a store in their app. It also process financial transactions associated with the purchase of content and services.

WebKit provides a set of classes to display web content in windows, and implements browser features such as following links when clicked by the user, managing a back-forward list, and managing a history of pages recently visited.

Render advanced 3D graphics and perform data-parallel computations. Get fine-grained access to the GPU while minimizing CPU overhead. The Metal Framework provides extremely low-overhead access to the GPU, enabling incredibly high performance for your sophisticated graphics rendering and computational tasks. Metal eliminates many performance bottlenecks—such as costly state validation—that are found in traditional graphics APIs. Metal moves all expensive state translation and compilation operations out of the critical path of your most performance sensitive rendering code. It provides precompiled shaders, state objects, and explicit command scheduling to ensure that your application achieves the highest possible performance and efficiency. Graphics, compute, and blit commands can be used together seamlessly and efficiently. Metal is specifically designed to exploit modern architectural considerations, such as multiprocessing and shared memory, to make it easy to parallelize the creation of GPU commands.

Bolts is a collection of low-level libraries designed to make developing mobile apps easier.