In this case study, we will highlight some key features of FoundationDB and the Record Layer that help us build CloudKit, Apple’s cloud storage system for structured data. We will focus on three key areas where FoundationDB and the Record Layer have unlocked large benefits for CloudKit. First, FoundationDB’s arbitrary multi-key ACID transactions have allowed us to implement advanced secondary indexing at scale, including our recently-developed transactional full-text search system. Second, the Record Layer’s version indexes have greatly increased the scalability of CloudKit’s core cross-device synchronization functionality. Finally, FoundationDB’s best-in-class reliability has simplified our operations, especially while recovering from failures. All together, FoundationDB has allowed us to provide richer APIs, greater scalability, and higher availability across billions of databases.
