JSON to C# Class Generator
LiveGenerate C# POCO classes from JSON objects automatically.
Understanding JSON (JavaScript Object Notation)
C# applications consume JSON data from RESTful APIs, configuration files, and external services — but C# is a statically-typed language that requires explicit class definitions (POCOs — Plain Old CLR Objects) to properly deserialize JSON. System.Text.Json and Newtonsoft.Json (Json.NET) both map JSON properties to C# class properties, but they need class definitions that match the JSON structure. Manually writing C# classes from complex, nested JSON responses is tedious and error-prone — mismatched property types, missed nullable fields, and incorrect nesting cause runtime deserialization failures.
Automatically generate strongly-typed C# POCO classes from JSON data. Creates proper class hierarchies for nested objects, handles arrays, and generates appropriate C# type annotations. Supports nullable types, JSON property attributes, and configurable class naming. Perfect for building .NET API clients and data models.
The Devkitr JSON to C# Converter generates C# class definitions from sample JSON data. Paste a JSON response to get properly-typed POCO classes with nullable annotations and JsonPropertyName attributes — ready for System.Text.Json or Newtonsoft.Json deserialization.
In a typical development workflow, JSON to C# Class Generator becomes valuable whenever you need to generate c# poco classes from json objects automatically. Whether you are working on a personal side project, maintaining production applications for a company, or collaborating with a distributed team across time zones, having a reliable browser-based conversion tool eliminates the need to install desktop software, write one-off scripts, or send data to third-party services that may log or retain your information. Since JSON to C# Class Generator processes everything locally on your device, your data stays private and your workflow stays uninterrupted — open a browser tab, paste your input, get your result.
Key Features
Type Inference
Analyzes JSON values to infer C# types — strings, ints, doubles, booleans, DateTimes, and nested objects — with nullable annotations for optional fields.
Nested Class Generation
Creates separate C# classes for nested JSON objects, maintaining proper hierarchy and naming derived from JSON property names.
Serializer Attribute Support
Generates [JsonPropertyName] for System.Text.Json or [JsonProperty] for Newtonsoft.Json when JSON field names differ from C# naming conventions.
Naming Convention Mapping
Converts snake_case and camelCase JSON keys to PascalCase C# property names following .NET naming conventions.
How to Use JSON to C# Class Generator
Paste JSON Data
Enter a sample JSON response from your API. Use a complete response that includes all possible fields, including nullable and nested objects.
Configure Options
Select the JSON serializer (System.Text.Json or Newtonsoft.Json), nullable reference type annotations, and root class name.
Review Generated Classes
Examine the generated C# classes for correct types, nullable annotations, and property attributes.
Copy to Your Project
Copy the generated classes into your C# project's models directory and use them for API deserialization.
Use Cases
API Client Development
Generate response model classes from API documentation or actual responses to build strongly-typed HTTP clients with proper deserialization.
.NET Configuration Binding
Create configuration classes that map to JSON configuration sections in appsettings.json for type-safe IOptions<T> binding.
Data Migration
Generate C# classes from JSON data files when migrating data into .NET applications from Node.js, Python, or other JSON-producing systems.
Third-Party API Integration
Quickly create model classes for Stripe, GitHub, Azure, or any external API by pasting their JSON response samples.
Pro Tips
Use multiple JSON samples that cover all possible field combinations. A single sample may miss nullable fields that appear only in certain responses.
Add [JsonIgnore] manually to properties you want to exclude from serialization — the generator includes all JSON fields by default.
For .NET 7+, prefer System.Text.Json with source generators for AOT compilation support and better performance.
Review generated DateTime types — JSON date strings might need custom converters if they use non-standard formats.
Common Pitfalls
Generating classes from incomplete JSON samples missing optional fields
Fix: Use comprehensive API responses that include all fields. Check API documentation for nullable/optional fields and add them to your sample.
Not marking nullable properties when JSON fields can be absent
Fix: Enable nullable reference types and mark properties as string? or int? when the JSON field may be null or missing in some responses.
Using generated classes directly as database entities
Fix: Generated classes are API DTOs. Create separate entity classes for database models — they have different concerns (EF navigation properties vs JSON serialization).
Frequently Asked Questions
QWhat C# types are generated?
String, int, long, double, bool, DateTime, List<T>, and nested custom classes are generated based on JSON value analysis.
QDoes it add JsonProperty attributes?
Yes. You can toggle JSON property attributes for Newtonsoft.Json or System.Text.Json serialization.
QHow are nested objects handled?
Nested JSON objects become separate C# classes with PascalCase naming derived from the JSON key names.
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