Schemas for JSON optimized for code generation

package user

import "time"

type User struct {
	CreatedAt time.Time `json:"created_at"`
	ID        string    `json:"id"`
	IsAdmin   bool      `json:"isAdmin"`
	Karma     int32     `json:"karma"`
}

package com.example;

import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.databind.annotation.JsonSerialize;
import java.time.OffsetDateTime;

@JsonSerialize
public class User {
    @JsonProperty("createdAt")
    private OffsetDateTime createdAt;

    @JsonProperty("id")
    private String id;

    @JsonProperty("isAdmin")
    private Boolean isAdmin;

    @JsonProperty("karma")
    private Integer karma;

    public User() {
    }

    public OffsetDateTime getCreatedAt() {
        return this.createdAt;
    }

    public void setCreatedAt(OffsetDateTime createdAt) {
        this.createdAt = createdAt;
    }

    public String getId() {
        return this.id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public Boolean getIsAdmin() {
        return this.isAdmin;
    }

    public void setIsAdmin(Boolean isAdmin) {
        this.isAdmin = isAdmin;
    }

    public Integer getKarma() {
        return this.karma;
    }

    public void setKarma(Integer karma) {
        this.karma = karma;
    }
}

using System;
using System.Text.Json.Serialization;

namespace Contoso.Example
{
    public class User
    {
        [JsonPropertyName("createdAt")]
        public DateTimeOffset CreatedAt { get; set; }

        [JsonPropertyName("id")]
        public string Id { get; set; }

        [JsonPropertyName("isAdmin")]
        public bool IsAdmin { get; set; }

        [JsonPropertyName("karma")]
        public int Karma { get; set; }
    }
}

from dataclasses import dataclass
from typing import Any, Optional, Union, get_args, get_origin

@dataclass
class User:
    created_at: 'str'
    id: 'str'
    is_admin: 'bool'
    karma: 'int'

    @classmethod
    def from_json(cls, data) -> "User":
        """
        Construct an instance of this class from parsed JSON data.
        """

        return cls(
            _from_json(str, data.get("createdAt")),
            _from_json(str, data.get("id")),
            _from_json(bool, data.get("isAdmin")),
            _from_json(int, data.get("karma")),
        )

    def to_json(self):
        """
        Generate JSON-ready data from an instance of this class.
        """

        out = {}
        out["createdAt"] = _to_json(self.created_at)
        out["id"] = _to_json(self.id)
        out["isAdmin"] = _to_json(self.is_admin)
        out["karma"] = _to_json(self.karma)
        return out

def _from_json(cls, data):
    if data is None or cls in [bool, int, float, str, object] or cls is Any:
        return data
    if get_origin(cls) is Union:
        return _from_json(get_args(cls)[0], data)
    if get_origin(cls) is list:
        return [_from_json(get_args(cls)[0], d) for d in data]
    if get_origin(cls) is dict:
        return { k: _from_json(get_args(cls)[1], v) for k, v in data.items() }
    return cls.from_json(data)

def _to_json(data):
    if data is None or type(data) in [bool, int, float, str, object]:
        return data
    if type(data) is list:
        return [_to_json(d) for d in data]
    if type(data) is dict:
        return { k: _to_json(v) for k, v in data.items() }
    return data.to_json()

# You can optionally generate .rbs too! (scroll to botton)

require 'json'
require 'time'

module Example
  class User
    attr_accessor :created_at
    attr_accessor :id
    attr_accessor :is_admin
    attr_accessor :karma

    def self.from_json_data(data)
      out = User.new
      out.created_at = Example::from_json_data(DateTime, data["createdAt"])
      out.id = Example::from_json_data(String, data["id"])
      out.is_admin = Example::from_json_data(TrueClass, data["isAdmin"])
      out.karma = Example::from_json_data(Integer, data["karma"])
      out
    end

    def to_json_data
      data = {}
      data["createdAt"] = Example::to_json_data(created_at)
      data["id"] = Example::to_json_data(id)
      data["isAdmin"] = Example::to_json_data(is_admin)
      data["karma"] = Example::to_json_data(karma)
      data
    end
  end

  private

  def self.from_json_data(type, data)
    if data.nil? || [Object, TrueClass, Integer, Float, String].include?(type)
      data
    elsif type == DateTime
      DateTime.rfc3339(data)
    elsif type.is_a?(Array)
      data.map { |elem| from_json_data(type.first, elem) }
    elsif type.is_a?(Hash)
      data.transform_values { |elem| from_json_data(type.values.first, elem) }
    else
      type.from_json_data(data)
    end
  end

  def self.to_json_data(data)
    if data.nil? || [TrueClass, FalseClass, Integer, Float, String].include?(data.class)
      data
    elsif data.is_a?(DateTime)
      data.rfc3339
    elsif data.is_a?(Array)
      data.map { |elem| to_json_data(elem) }
    elsif data.is_a?(Hash)
      data.transform_values { |elem| to_json_data(elem) }
    else
      data.to_json_data
    end
  end
end

# If you enable it, you'll also get a .rbs file:

module Example
  class User
    attr_accessor created_at: DateTime
    attr_accessor id: String
    attr_accessor is_admin: bool
    attr_accessor karma: Integer

    def self.from_json_data: (untyped) -> User
    def to_json_data: () -> untyped
  end

  def self.from_json_data: (untyped, untyped) -> untyped
  def self.to_json_data: (untyped) -> untyped
end

use chrono::{DateTime, FixedOffset};
use serde::{Deserialize, Serialize};

#[derive(Serialize, Deserialize)]
pub struct User {
    #[serde(rename = "createdAt")]
    pub createdAt: DateTime<FixedOffset>,

    #[serde(rename = "id")]
    pub id: String,

    #[serde(rename = "isAdmin")]
    pub isAdmin: bool,

    #[serde(rename = "karma")]
    pub karma: i32,
}