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JSON to C# Converter

JSON is a lightweight, human-readable key-value format — widely used for REST API responses, configuration files, NoSQL documents. Converting it to strongly-typed C# structures eliminates runtime surprises and speeds up development. This tool does it in one click, entirely in your browser.

Generate C# classes with JsonPropertyName attributes for System.Text.Json or Newtonsoft compatibility.

How to use this converter

  1. Paste your JSON into the left editor panel
  2. Click Generate
  3. Copy the generated C# code from the right panel

No account. No upload. No tracking. Runs entirely in your browser.

Example C# output

using System.Text.Json.Serialization;
 
public class Address {
    [JsonPropertyName("city")]
    public string City { get; set; } = string.Empty;
 
    [JsonPropertyName("zip")]
    public string Zip { get; set; } = string.Empty;
}
 
public class User {
    [JsonPropertyName("id")]
    public long Id { get; set; }
 
    [JsonPropertyName("name")]
    public string Name { get; set; } = string.Empty;
 
    [JsonPropertyName("email")]
    public string? Email { get; set; }
}

Why automate JSON-to-C# conversion?

Writing C# class / record definitions by hand from JSON is:

  • Tedious — especially for deeply nested or large JSON payloads
  • Inconsistent — naming conventions drift when done manually across a team
  • Fragile — when the JSON schema changes, hand-written models lag behind

C# records (C# 9+) provide immutable, value-semantic data models — ideal for DTOs in modern .NET applications.

This converter handles all of that automatically, giving you idiomatic C# code that matches your JSON structure exactly.

C# and JSON: what you need to know

C# is a object-oriented, strongly typed language, .NET standard for ASP.NET Core, Unity, and enterprise apps. It uses class/record based with System.Text.Json or Newtonsoft for structured data — making it a natural fit for JSON-driven applications.

What the converter generates

Output produces C# POCO classes with [JsonPropertyName] attributes and nullable reference types (string?) for optional fields. Nested objects become separate classes in the same namespace.

A common gotcha

C# nullable reference types (string?) require the #nullable enable directive — the converter targets modern C# 10+ conventions.

JSON input characteristics

JSON supports nested objects, arrays, strings, numbers, booleans, and null. Tools like jq, Postman, and browser DevTools make JSON the most developer-friendly data exchange format.

When should I use this converter?

Use this when building ASP.NET Core APIs or .NET microservices that consume external data sources and need strongly-typed, annotated model classes.

Common use cases

  • Generating POCOs for ASP.NET Core Web API request/response models
  • Creating typed models for HttpClient-based API consumption in .NET apps
  • Producing C# classes for Azure Functions that process event payloads
  • Rapid prototyping with real JSON payloads
  • Keeping C# structs in sync when JSON schemas evolve
  • Onboarding new team members by auto-generating the data layer
  • Validating JSON contract compatibility with C# type definitions
  • Generating C# models from ASP.NET Core APIs API responses
  • Creating typed DTOs for Unity games

Frequently asked questions

Does this converter support JavaScript Object Notation namespaces and nested structures?

Yes. JSON is natively parsed by all major runtimes — no schema required to begin parsing. The parser handles deeply nested structures and generates matching nested C# class / record definitions.

How are optional fields handled in the C# output?

Fields that may be absent or null in your JSON are marked as optional in the generated C# code. Note: C# nullable reference types (string?) require the #nullable enable directive — the converter targets modern C# 10+ conventions.

Can I use the output directly in a ASP.NET Core APIs project?

Yes. The generated C# code follows idiomatic patterns for ASP.NET Core APIs — you can copy it directly into your project.

Does this work for large JSON payloads?

Yes. The converter is optimized for large and deeply nested JSON structures, running entirely in the browser without page reloads or server round-trips.

Related tools on LangStop

If you work frequently with JSON and C#, bookmark this page to skip the manual model-writing step entirely.