---
title: Foundation
framework: Foundation
role: collection
role_heading: Framework
platforms: [iOS 2.0+, iPadOS 2.0+, Mac Catalyst 13.0+, macOS 10.0+, tvOS 9.0+, visionOS 1.0+, watchOS 2.0+]
path: foundation
---

# Foundation

Access essential data types, collections, and operating-system services to define the base layer of functionality for your app.

## Overview

Overview The Foundation framework provides a base layer of functionality for apps and frameworks, including data storage and persistence, text processing, date and time calculations, sorting and filtering, and networking. The classes, protocols, and data types defined by Foundation are used throughout the macOS, iOS, watchOS, and tvOS SDKs.

## Topics

### Fundamentals

- [Numbers, Data, and Basic Values](foundation/numbers-data-and-basic-values.md)
- [Strings and Text](foundation/strings-and-text.md)
- [Collections](foundation/collections.md)
- [Dates and Times](foundation/dates-and-times.md)
- [Units and Measurement](foundation/units-and-measurement.md)
- [Data Formatting](foundation/data-formatting.md)
- [Filters and Sorting](foundation/filters-and-sorting.md)

### App Support

- [Task Management](foundation/task-management.md)
- [Resources](foundation/resources.md)
- [Notifications](foundation/notifications.md)
- [App Extension Support](foundation/app-extension-support.md)
- [Errors and Exceptions](foundation/errors-and-exceptions.md)
- [Scripting Support](foundation/scripting-support.md)

### Files and Data Persistence

- [File System](foundation/file-system.md)
- [Archives and Serialization](foundation/archives-and-serialization.md)
- [Settings](foundation/settings.md)
- [Spotlight](foundation/spotlight.md)
- [iCloud](foundation/icloud.md)
- [Optimizing Your App’s Data for iCloud Backup](foundation/optimizing-your-app-s-data-for-icloud-backup.md)

### Networking

- [URL Loading System](foundation/url-loading-system.md)
- [Bonjour](foundation/bonjour.md)

### Low-Level Utilities

- [XPC](foundation/xpc.md)
- [Object Runtime](foundation/object-runtime.md)
- [Processes and Threads](foundation/processes-and-threads.md)
- [Streams, Sockets, and Ports](foundation/streams-sockets-and-ports.md)

### Reference

- [Foundation Enumerations](foundation/foundation-enumerations.md)
- [Foundation Data Types](foundation/foundation-data-types.md)

### Classes

- [ProgressManager](foundation/progressmanager.md)
- [ProgressReporter](foundation/progressreporter.md)

### Protocols

- [NSPredicateValidating](foundation/nspredicatevalidating.md)

### Structures

- [Subprogress](foundation/subprogress.md)