Convert JSON to TypeScript, Python & Go Types

Manually typing API responses creates friction, causes synchronization bugs, and introduces human typing mistakes. Automating type definitions ensures compile-time error checking, rich IDE autocompletion, and zero-overhead validation across distributed architectures.

1. TypeScript: Interfaces vs Type Aliases

When mapping JSON payloads to TypeScript, nested structures should be broken down into composable interfaces. Optional keys must be demarcated with the ? operator, and union types should represent variable schema payloads.

export interface UserResponse {
  id: string;
  name: string;
  email: string;
  isActive: boolean;
  roles: Array<'admin' | 'editor' | 'viewer'>;
  profile: UserProfile;
  lastLogin?: string; // Optional field
}

export interface UserProfile {
  avatarUrl: string | null;
  timezone: string;
  preferences: Record;
}

2. Python: Pydantic v2 vs Dataclasses

In modern Python (3.10+), developers commonly choose between standard library @dataclass for lightweight models, or Pydantic v2 for runtime data coercion and strict schema enforcement.

from typing import List, Optional, Dict
from pydantic import BaseModel, Field, HttpUrl
from datetime import datetime

class UserProfile(BaseModel):
    avatar_url: Optional[str] = None
    timezone: str = "UTC"
    preferences: Dict[str, bool] = Field(default_factory=dict)

class UserResponse(BaseModel):
    id: str
    name: str
    email: str
    is_active: bool
    roles: List[str]
    profile: UserProfile
    last_login: Optional[datetime] = None

    class Config:
        populate_by_name = True

3. Go: Structs with JSON Tags &

Go requires struct tags to map uppercase exported struct fields to camelCase or snake_case JSON keys. Use omitempty when generating payload encoders to omit zero-value fields from outbound JSON strings.

package models

import "time"

type UserProfile struct {
	AvatarURL   *string         
	Timezone    string          
	Preferences map[string]bool 
}

type UserResponse struct {
	ID        string      
	Name      string      
	Email     string      
	IsActive  bool        
	Roles     []string    
	Profile   UserProfile 
	LastLogin *time.Time  
}

Instant 1-Click Code Generation

Instead of handwriting hundreds of lines of boilerplate models, open JSONLints Studio, paste any sample JSON payload, switch to the TypeScript or Code converter, and copy production-ready type definitions instantly.