JSON to Objective-C Converter

Paste a JSON object and generate Objective-C model classes with typed properties, nested classes, and optional dictionary mapping helpers.

Last updated: May 28, 2026

Root class:Prefix:Nullable object propertiesDictionary mapper

JSON Input

Generated Objective-C Classes

#import <Foundation/Foundation.h>



@interface WTPProfile : NSObject
@property (nonatomic, copy, nullable) NSString *city;
@property (nonatomic, assign) double score;
+ (instancetype)modelWithDictionary:(NSDictionary *)dictionary;
@end

@implementation WTPProfile
+ (instancetype)modelWithDictionary:(NSDictionary *)dictionary {
    WTPProfile *model = [[self alloc] init];
    if ([dictionary[@"city"] isKindOfClass:[NSString class]]) {
        model.city = dictionary[@"city"];
    }
    model.score = [dictionary[@"score"] doubleValue];
    return model;
}
@end

@interface WTPRoot : NSObject
@property (nonatomic, assign) NSInteger userId;
@property (nonatomic, copy, nullable) NSString *name;
@property (nonatomic, assign) BOOL active;
@property (nonatomic, strong, nullable) WTPProfile *profile;
@property (nonatomic, copy, nullable) NSArray<NSString *> *roles;
+ (instancetype)modelWithDictionary:(NSDictionary *)dictionary;
@end

@implementation WTPRoot
+ (instancetype)modelWithDictionary:(NSDictionary *)dictionary {
    WTPRoot *model = [[self alloc] init];
    model.userId = [dictionary[@"userId"] integerValue];
    if ([dictionary[@"name"] isKindOfClass:[NSString class]]) {
        model.name = dictionary[@"name"];
    }
    model.active = [dictionary[@"active"] boolValue];
    if ([dictionary[@"profile"] isKindOfClass:[NSDictionary class]]) {
        model.profile = [WTPProfile modelWithDictionary:dictionary[@"profile"]];
    }
    if ([dictionary[@"roles"] isKindOfClass:[NSArray class]]) {
        model.roles = dictionary[@"roles"];
    }
    return model;
}
@end

Client-Side Processing

Input Data Stays on Device

Instant Local Execution

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What is JSON to Objective-C Converter?

Objective-C codebases often represent API responses as NSObject model classes. Turning a JSON sample into those classes by hand is repetitive: each JSON key needs a property, scalar values need the right primitive or Foundation type, nested objects need their own classes, and arrays need the right NSArray generic annotation.

This converter reads a JSON object and creates a starter Objective-C model layer. Strings become NSString, integers become NSInteger, decimals become double, booleans become BOOL, arrays become NSArray, and nested objects become separate classes. When mapper generation is enabled, each class also includes a modelWithDictionary: method that assigns values from an NSDictionary.

How to Use JSON to Objective-C Converter

Paste a JSON object into the input panel.

Choose a root class name and optional class prefix.

Toggle nullable annotations and dictionary mapper methods.

Copy or download the generated Objective-C code.

Review the output and adjust property names or custom parsing logic for production code.

Common Use Cases

Creating iOS model classes from a REST API response.
Migrating JSON fixtures into Objective-C NSObject models.
Bootstrapping dictionary-to-model mapper code for legacy apps.
Documenting expected response shapes in an Objective-C codebase.
Generating starter classes before adding custom validation or parsing.

Example Input and Output

A nested JSON object generates a root class and a nested profile class.

JSON input

{ "userId": 42, "name": "Alice", "profile": { "city": "London" } }

Objective-C output

@interface WTPRoot : NSObject
@property (nonatomic, assign) NSInteger userId;
@property (nonatomic, copy, nullable) NSString *name;
@property (nonatomic, strong, nullable) WTPProfile *profile;
@end

Privacy

All generation happens locally in your browser. JSON input is not uploaded.

Model naming

Use a project-specific class prefix to avoid collisions with Apple frameworks and third-party Objective-C classes.

Frequently Asked Questions

Does this create .h and .m files separately?

The output includes interfaces and implementations together for easy copying. Split them into .h and .m files if that matches your project style.

How are JSON arrays handled?

Arrays become NSArray properties. Arrays of objects get a nested class type such as NSArray<WTPItem *> *, while primitive arrays use Foundation object types.

Can this infer custom date types?

No. JSON dates are strings, so the generated property starts as NSString. Convert it to NSDate or another type manually if your app needs date parsing.

Are dictionary mapper methods production-ready?

They are useful starter code. For production, add validation, date parsing, enum mapping, and stronger null handling as needed.

Does this send JSON to a server?

No. Generation runs locally in your browser.