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KumarAdi8
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swift-codable

Encode and decode Swift data structures for JSON and property-list serialization.

Updated Aug 27, 2026
Search Tags:#json#swift#encoding#decoding#codable#urlsession
One-click install
npx skills add https://github.com/KumarAdi8/AgentKit --skill swift-codable-kumaradi8
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: swift-codable
Source: https://github.com/KumarAdi8/AgentKit/tree/main/skills/swift-codable
Command: npx skills add https://github.com/KumarAdi8/AgentKit --skill swift-codable-kumaradi8

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Mapping JSON and property-list data to strongly typed Swift models is error prone and time consuming, especially when APIs use different key naming, nested structures, inconsistent arrays, or varied date formats. This Skill provides patterns and guidance to reliably decode incoming data, encode outgoing payloads, and integrate serialization with networking and local storage.

Core Features & Use Cases

  • Automatic Codable synthesis for simple models and guidance on choosing Encodable, Decodable, or Codable.
  • Custom CodingKeys, nested container handling, and custom init(from:) / encode(to:) for transformations and flattened JSON.
  • Date, data, and key decoding/encoding strategies, lossy array decoding, single-value containers, and deterministic encoder configuration for tests.
  • Integration examples for URLSession networking, SwiftData composite attributes, and storing Codable types in UserDefaults.
  • Real-world use case: decode heterogeneous content arrays from an API, remap snake_case keys to camelCase, and supply defaults for missing fields.

Quick Start

Decode an API response into a Swift model by configuring JSONDecoder with the appropriate date and key strategies and then decode the top-level payload into your Decodable type.

Frequently Asked Questions about swift-codable

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I decode JSON with snake_case keys into Swift Codable models?▼

To decode heterogeneous arrays in Swift Codable, implement a custom init(from:) method using nested unkeyed containers and single-value containers to inspect and decode mixed types within the same JSON array safely.

How do I decode heterogeneous arrays in Swift Codable?▼

To decode heterogeneous arrays in Swift Codable, implement a custom init(from:) method using nested unkeyed containers and single-value containers to inspect and decode mixed types within the same JSON array safely.

What is the best way to handle custom date formats when decoding JSON in Swift?▼

To flatten nested JSON structures in Swift Codable, implement custom encoding and decoding logic with nested containers, or override encode(to:) and init(from:) to map nested keys directly to top-level properties.

Can I use Swift Codable with URLSession for API networking?▼

Yes, Swift Codable integrates with UserDefaults by using JSONEncoder to serialize custom objects into Data before storing, and JSONDecoder to deserialize that Data back into Decodable types upon retrieval.

How do I handle missing fields when decoding JSON in Swift?▼

To handle missing fields when decoding JSON in Swift, implement custom init(from:) logic to supply default values, or use lossy decoding techniques to skip invalid array elements without failing the entire parse.

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