JSON to Objective-C Model Converter

Paste JSON, get Objective-C models — @interface, @implementation, initWithDictionary — copy or download

All processing happens in your browser. No data is sent to any server.

Options

Class name:

Prefix:

JSON Input

Objective-C Output

#import <Foundation/Foundation.h>

@class Root;
@class Address;
@interface Address : NSObject

@property (copy, nonatomic) NSString *street;
@property (copy, nonatomic) NSString *city;
@property (copy, nonatomic) NSString *zip;

- (instancetype)initWithDictionary:(NSDictionary *)dictionary;
- (NSDictionary *)toDictionary;

@end


@implementation Address

- (instancetype)initWithDictionary:(NSDictionary *)dictionary {
    self = [super init];
    if (self) {
        _street = dictionary[@"street"];
        _city = dictionary[@"city"];
        _zip = dictionary[@"zip"];
    }
    return self;
}

- (NSDictionary *)toDictionary {
    NSMutableDictionary *dict = [NSMutableDictionary dictionary];
    if (self.street) dict[@"street"] = self.street;
    if (self.city) dict[@"city"] = self.city;
    if (self.zip) dict[@"zip"] = self.zip;
    return [dict copy];
}

@end


@interface Root : NSObject

@property (strong, nonatomic) NSNumber *id;
@property (copy, nonatomic) NSString *name;
@property (copy, nonatomic) NSString *email;
@property (strong, nonatomic) NSNumber *age;
@property (assign, nonatomic) BOOL isActive;
@property (strong, nonatomic) NSNumber *score;
@property (strong, nonatomic) Address *address;
@property (strong, nonatomic) NSArray *tags;
@property (strong, nonatomic) NSArray *posts;

- (instancetype)initWithDictionary:(NSDictionary *)dictionary;
- (NSDictionary *)toDictionary;

@end


@implementation Root

- (instancetype)initWithDictionary:(NSDictionary *)dictionary {
    self = [super init];
    if (self) {
        _id = dictionary[@"id"];
        _name = dictionary[@"name"];
        _email = dictionary[@"email"];
        _age = dictionary[@"age"];
        _isActive = [dictionary[@"isActive"] boolValue];
        _score = dictionary[@"score"];
        _address = [[Address alloc] initWithDictionary:dictionary[@"address"]];
        _tags = dictionary[@"tags"];
        _posts = dictionary[@"posts"];
    }
    return self;
}

- (NSDictionary *)toDictionary {
    NSMutableDictionary *dict = [NSMutableDictionary dictionary];
    if (self.id) dict[@"id"] = self.id;
    if (self.name) dict[@"name"] = self.name;
    if (self.email) dict[@"email"] = self.email;
    if (self.age) dict[@"age"] = self.age;
    dict[@"isActive"] = @(self.isActive);
    if (self.score) dict[@"score"] = self.score;
    if (self.address) dict[@"address"] = [self.address toDictionary];
    if (self.tags) dict[@"tags"] = self.tags;
    if (self.posts) dict[@"posts"] = self.posts;
    return [dict copy];
}

@end

Output: 2,529 charsClasses: 2

You’re maintaining an Objective-C codebase that consumes a REST API. The JSON response has 30 fields with nested objects. Writing @property declarations by hand for every field — choosing between NSString *, NSNumber *, NSArray<ClassName *> * — is tedious and error-prone.

What This Tool Does

Paste JSON and get Objective-C model classes instantly. You get both the @interface (header) and @implementation with initWithDictionary: methods. Nested objects become separate model classes. Arrays of objects use proper generic annotations.

Everything runs in your browser. Your data never leaves your device.

Type Mapping

JSON type	Objective-C type
`"hello"`	`NSString *`
`42`	`NSNumber *`
`3.14`	`NSNumber *`
`true`	`NSNumber *` (BOOL)
`null`	`id`
`[{...}]`	`NSArray<ClassName > `
`{...}`	custom model class

When to Use This

Legacy iOS/macOS apps — generate models for APIs consumed by Objective-C code
Mixed Swift/ObjC projects — create ObjC models that bridge to Swift
macOS development — scaffold model classes for JSON-based APIs
Core Data integration — use generated models as a reference for managed object subclasses

FAQ

Does this send my JSON to a server?

No. All processing happens entirely in your browser using JavaScript.

How are property names formatted?

JSON keys are converted to camelCase Objective-C property names. Snake_case keys like first_name become firstName.

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