File Provider Sync Engineer

Every day, hundreds of millions of people trust their documents to iCloud Drive, Dropbox, OneDrive, Google Drive and Box on Apple platforms. These services rely on a common foundation built at the core of our operating systems, the File Provider framework, APIs and daemons developed by a Core OS team in Paris. We are responsible for keeping users’ files consistent across their devices and services, and the deep system integration that provides the best local user experience with cloud-backed files.

We are looking for a systems engineer who wants to work where distributed state meets the operating system. You do not need to have sync experience. You do need to care deeply about getting things right, because at our scale, rare bugs have the potential to cause dataloss for many users.

You will join the team that owns the sync engine: the system that detects, tracks and applies changes flowing in both directions between a device and the cloud. The central problem is reconciling two trees that change independently: the local filesystem where users save their files, and remote services we don’t control. The engine plans and executes a graph of dependent operations to apply each change to the other tree, in an order that never breaks the folder structure, even through concurrent edits, crashes and conflicts.

The workload is heavily bursty: we track millions of files, and a single event can change a large share of them at once. On iPhone and iPad, absorbing those bursts means competing with apps and daemons for memory, CPU, battery and storage.

You will contribute to a system that walks a constant tightrope: careful enough that it never loses data, fast enough that sync feels instant, and light enough that nobody notices it running. Day to day, you will design, implement, test and debug new features, quality safeguards and performance improvements. Initially, you will be paired with experts who will accompany you on scoped assignments, and you will build autonomy and ownership from there. You will collaborate closely with engineering teams worldwide, from kernel to cloud, across our operating systems and services stack, and external developers adopting our APIs throughout the industry.

Solid programming skills in a systems language such as C, C++, Objective-C or Swift

Working understanding of operating system fundamentals: processes, concurrency, memory, file I/O

Demonstrated ability to debug methodically

Clear written and verbal communication in English, and a collaborative approach to working across teams

Curiosity about how systems actually work underneath the abstractions

Experience reasoning about stateful systems that must stay correct across crashes, restarts, partial failures or concurrent mutation

Exposure to distributed systems concepts: eventual consistency, change tracking, reconciliation, conflict resolution

Familiarity with filesystems, APFS or otherwise, or with filesystem-adjacent system components

Experience with performance, memory or energy profiling

Experience maintaining an API or library that other developers depend on

Experience with agentic coding

Contributions to a large, long-lived codebase