# IOS Networking

Build, review, or improve networking code in iOS/macOS apps using URLSession with...

- Repository: https://github.com/dpearson2699/swift-ios-skills (1266 stars)
- Category: Mobile
- License: see repository
- Last updated: 2026-07-31
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add dpearson2699/swift-ios-skills --skill ios-networking -g -a claude-code -y`
Codex: `npx skills add dpearson2699/swift-ios-skills --skill ios-networking -g -a codex -y`
Cursor: `npx skills add dpearson2699/swift-ios-skills --skill ios-networking -g -a cursor -y`
Gemini CLI: `npx skills add dpearson2699/swift-ios-skills --skill ios-networking -g -a gemini-cli -y`
Claude Code plugin marketplace: `/plugin marketplace add dpearson2699/swift-ios-skills`

## Description

Build, review, or improve networking code in iOS/macOS apps using URLSession with async/await, structured concurrency, and modern Swift patterns. Use when working with REST APIs, downloading files, uploading data, WebSocket connections, pagination, retry logic, request middleware, caching, background transfers, or network reachability monitoring. Also use when handling HTTP requests, API clients, network error handling, or data fetching in Swift apps.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# iOS Networking

Use URLSession with async/await and structured concurrency for ordinary HTTP,
REST, uploads, downloads, and streaming. Use Network.framework for lower-level
protocols and delegate/task APIs for durable background transfers.

## Contents

- [Core URLSession async/await](#core-urlsession-asyncawait)
- [API Client Architecture](#api-client-architecture)
- [Error Handling](#error-handling)
- [Pagination](#pagination)
- [Network Reachability](#network-reachability)
- [Configuring URLSession](#configuring-urlsession)
- [App Transport Security (ATS)](#app-transport-security-ats)
- [Common Mistakes](#common-mistakes)
- [Review Checklist](#review-checklist)
- [References](#references)

## Core URLSession async/await

URLSession gained native async/await overloads in iOS 15. Prefer these for
foreground data, upload, download, and streaming work. Background URLSession
transfers are the main exception: they still use task/delegate APIs so the
system can deliver events after suspension or relaunch.

Validate networking policy locally with `URLProtocol` fixtures for valid 2xx,
malformed 2xx, one-time 401 refresh, bounded 429/5xx retry, timeout/offline,
cancellation, and nonretryable 4xx. Inspect headers, status, and error
classification; fix the policy and rerun. Retry only safe/idempotent or
explicitly replayable requests, and never loop token refresh.

### Data Requests

```swift
// Basic GET
let (data, response) = try await URLSession.shared.data(from: url)

// With a configured URLRequest
var request = URLRequest(url: url)
request.httpMethod = "POST"
request.setValue("application/json", forHTTPHeaderField: "Content-Type")
request.httpBody = try JSONEncoder().encode(payload)
request.timeoutInterval = 30
request.cachePolicy = .reloadIgnoringLocalCacheData

let (data, response) = try await URLSession.shared.data(for: request)
```

### Response Validation

The rest: https://github.com/dpearson2699/swift-ios-skills/blob/HEAD/skills/ios-networking/SKILL.md