An SDK, or software development kit, is a set of developer tools built to assist developers in building applications. This can be broad in that an SDK can be built to assist with developing an application for an operating system such as iOS or it can be more focused on developing specific features, like the Branch SDK—designed to utilize the Branch platform to help with deep linking and attribution.

SDKs are often provided to encourage development within a platform because they simplify the development process. The best SDKs provide extensive documentation allowing developers to get up to speed as quickly as possible.