How to map nested JSON keys in JSONModel?

Use the keyMapper method in your model implementation to define mappings for nested paths—for example, mapping orderDetails.name to productName as shown in the README. This handles complex JSON without flattening your model structure.

JSONModel vs Codable in Swift: which is better?

JSONModel is best for Objective-C projects, offering automatic mapping and validation, while Codable is Swift-native and compile-time safe. For mixed codebases, JSONModel provides more features but with runtime overhead and bridging complexity.

How to handle optional properties in JSONModel?

Mark properties with the protocol to allow missing or null values in JSON. For scalar types like integers, override propertyIsOptional: to return YES, as demonstrated in the examples with id.

Can JSONModel convert models back to JSON?

Yes, use the toDictionary or toJSONString methods on model instances to export them back to JSON format. This is useful for serializing data for API calls, shown in the export example with ProductModel.

How to validate custom business logic in JSONModel?

Override the validate: method in your model implementation to add custom validation, such as checking string lengths or other constraints. The README shows an example where name length is validated against a minimum.

What are the installation options for JSONModel?

JSONModel can be installed via CocoaPods, Carthage, or manually by copying source files. CocoaPods is common with pod 'JSONModel', while manual setup requires linking SystemConfiguration.framework as per the README.

JSONModel — iOS JSON Model Framework

What is JSONModel?

JSONModel is a data modeling framework for Objective-C that automates the mapping of JSON data to native model objects. It eliminates manual parsing code by introspecting model classes and converting JSON values to the correct property types. The framework handles validation, optional properties, nested models, and custom transformations.

Target Audience

iOS, macOS, watchOS, and tvOS developers working with JSON APIs who want to reduce boilerplate parsing code and ensure type-safe data models.

Value Proposition

Developers choose JSONModel because it dramatically reduces the amount of code needed to parse and validate JSON, provides automatic type conversion, and supports complex scenarios like nested models and custom mappings while being lightweight and focused on the Apple ecosystem.

Magical Data Modeling Framework for JSON - allows rapid creation of smart data models. You can use it in your iOS, macOS, watchOS and tvOS apps.

Use Cases

Best For

Rapidly creating model classes from JSON APIs in Objective-C projects
Ensuring type safety when parsing JSON responses in iOS apps
Handling nested JSON structures with cascading models
Converting between JSON strings and native model objects
Adding custom validation logic to data models
Mapping JSON keys with different naming conventions (like snake_case) to camelCase properties

Not Ideal For

Projects written entirely in Swift without Objective-C interoperability
Applications processing non-JSON data formats like XML or binary streams
High-performance real-time systems where runtime introspection overhead is unacceptable
Teams preferring hand-rolled parsers for absolute control over data flow and dependencies

Pros & Cons

Pros

Automatic Property Mapping

Maps JSON keys to model properties based on naming conventions, drastically reducing boilerplate code—as shown in the basic usage example where no implementation file code is needed.

Flexible Type Conversion

Automatically converts JSON values (e.g., strings to integers, numbers to strings) to expected Objective-C types, demonstrated in the CountryModel example with id and dialCode.

Nested Model Support

Handles complex JSON structures through model cascading and collections, allowing properties to be other JSONModel instances or arrays, as illustrated with OrderModel and ProductModel.

Custom Key Mapping

Enables mapping JSON keys with different names or nested paths using keyMapper, useful for APIs with inconsistent naming like snake_case, shown in the nested key mapping example.

Cons

Objective-C Lock-in

Primarily designed for Objective-C; it lacks native Swift support and modern features like Codable, requiring bridging in Swift projects which adds complexity.

Protocol Requirement for Collections

Requires protocols for model collections, which can be confusing and conflict with Objective-C generics, as noted in the README's model collections example with NSArray <ProductModel>.

Runtime Overhead

Relies on runtime introspection for property mapping and validation, introducing performance penalties compared to compile-time solutions like Swift's Codable in some scenarios.

What is JSONModel?

Target Audience

iOS, macOS, watchOS, and tvOS developers working with JSON APIs who want to reduce boilerplate parsing code and ensure type-safe data models.

Value Proposition

Use Cases

Best For

Rapidly creating model classes from JSON APIs in Objective-C projects
Ensuring type safety when parsing JSON responses in iOS apps
Handling nested JSON structures with cascading models
Converting between JSON strings and native model objects
Adding custom validation logic to data models
Mapping JSON keys with different naming conventions (like snake_case) to camelCase properties

Not Ideal For

Projects written entirely in Swift without Objective-C interoperability
Applications processing non-JSON data formats like XML or binary streams
High-performance real-time systems where runtime introspection overhead is unacceptable
Teams preferring hand-rolled parsers for absolute control over data flow and dependencies

Pros & Cons

Pros

Automatic Property Mapping

Maps JSON keys to model properties based on naming conventions, drastically reducing boilerplate code—as shown in the basic usage example where no implementation file code is needed.

Flexible Type Conversion

Automatically converts JSON values (e.g., strings to integers, numbers to strings) to expected Objective-C types, demonstrated in the CountryModel example with id and dialCode.

Nested Model Support

Handles complex JSON structures through model cascading and collections, allowing properties to be other JSONModel instances or arrays, as illustrated with OrderModel and ProductModel.

Custom Key Mapping

Enables mapping JSON keys with different names or nested paths using keyMapper, useful for APIs with inconsistent naming like snake_case, shown in the nested key mapping example.

Cons

Objective-C Lock-in

Primarily designed for Objective-C; it lacks native Swift support and modern features like Codable, requiring bridging in Swift projects which adds complexity.

Protocol Requirement for Collections

Requires protocols for model collections, which can be confusing and conflict with Objective-C generics, as noted in the README's model collections example with NSArray <ProductModel>.

Runtime Overhead

Relies on runtime introspection for property mapping and validation, introducing performance penalties compared to compile-time solutions like Swift's Codable in some scenarios.

JSONModel

What is JSONModel?

Overview

Use Cases

Best For

Not Ideal For

Pros & Cons

Pros

Cons

Frequently Asked Questions

Found a gem we're missing?

JSONModel

What is JSONModel?

Overview

Use Cases

Best For

Not Ideal For

Pros & Cons

Pros

Cons

Frequently Asked Questions

Found a gem we're missing?