DevBolt
Processed in your browser. Your data never leaves your device.

How do I generate typed code from JSON?

Paste JSON data and select a language — Go, Python, Java, C#, Dart, Rust, Swift, or Kotlin — to generate typed structs, classes, or dataclasses with proper type inference, naming conventions, and serialization annotations. The tool handles nested objects, arrays, and null values. Everything runs in your browser.

JSON to Go struct
Input
{"id":1,"name":"Alice","email":"a@b.com","active":true}
Output
type Root struct {
    ID     int    `json:"id"`
    Name   string `json:"name"`
    Email  string `json:"email"`
    Active bool   `json:"active"`
}
← Back to tools

JSON to Code Generator

Generate typed code from JSON in 8 languages — Go structs, Python dataclasses, Java/C#/Dart/Kotlin classes, Rust/Swift structs. Handles nested objects, arrays, and null values.

Supported Languages

LanguageOutput TypeSerialization
GoStructs with json tagsencoding/json
PythonDataclasses with type hintsdataclasses
JavaClasses with getters/settersJackson / Gson
C#Classes with JsonPropertyNameSystem.Text.Json
DartClasses with fromJson/toJsondart:convert
RustStructs with serde deriveserde
SwiftCodable structsCodable
KotlinData classes with @Serializablekotlinx.serialization

How It Works

  • Nested objects — each nested object becomes a separate named type/class/struct, referenced by the parent.
  • Arrays — element types are inferred from the first item. Object arrays merge all items for complete field coverage.
  • Numbers — integers and floats are detected automatically (e.g., int64 vs float64 in Go).
  • Null values— mapped to each language's nullable/optional type (e.g., Any? in Kotlin, Option in Rust).
  • Naming conventions— field names follow each language's idiom (camelCase, snake_case, PascalCase) with JSON key annotations.
  • Everything runs in your browser — no data is sent over the network.

Tips & Best Practices

Pro Tip

Use generated types as a starting point, not the final schema

Auto-generated Go structs, Python dataclasses, and Rust structs infer types from sample data. A field with value 1 might be inferred as int when it should be float, or a missing nullable field won't be marked as optional. Always review generated types against your API documentation.

Common Pitfall

Sample data may not represent all possible field types

If your JSON sample has a null field, the generator can't determine the actual type (string? object?). If a field is sometimes an array and sometimes null, the generated type might miss the array case. Use the most complete sample data available — ideally from API docs, not a single response.

Real-World Example

Generate Go structs with json tags from API responses

Paste a JSON API response to get Go structs with correct json:"fieldName" tags. Go uses PascalCase for exported fields but APIs use camelCase or snake_case — the generated tags handle this mapping automatically, saving tedious manual struct creation.

Security Note

Never expose internal fields in generated API types

When generating types from a database record JSON, internal fields like password_hash, internal_id, or is_admin may appear. Remove these from your public-facing types. Use separate request/response types rather than sharing one struct that accidentally exposes sensitive fields.

Frequently Asked Questions

How do I generate typed code from JSON in Go, Python, or Rust?
Paste JSON into DevBolt's converter and select your target language. The tool generates: Go structs with json tags, Python dataclasses, Java classes with getters/setters, C# classes with JsonProperty attributes, Dart classes with fromJson/toJson, Rust structs with serde derives, Swift Codable structs, and Kotlin data classes. Nested objects create separate named types. Arrays infer element types. Null values generate nullable types. The output includes serialization boilerplate for each language's ecosystem.
How does the converter handle nested objects and mixed-type arrays?
Nested objects are extracted into separate named types based on the parent property name. Mixed-type arrays are handled per language: Go uses any, Python uses Union or Any, Rust uses serde_json::Value, Java uses Object, and TypeScript uses a union type. Arrays of objects with inconsistent keys generate types with optional fields covering all possible properties.
Which programming languages are supported?
DevBolt supports 8 languages: Go (structs with json tags), Python (dataclasses), Java (POJO with Jackson), C# (System.Text.Json attributes), Dart (fromJson factory constructors), Rust (serde Serialize/Deserialize), Swift (Codable structs), and Kotlin (data classes with kotlinx.serialization). Each output follows idiomatic conventions including proper naming (camelCase for Java, snake_case for Python/Rust, PascalCase for C#/Go).

Related Convert Tools

cURL

cURL to Code

Convert cURL commands to JavaScript, Python, Go, PHP, Ruby, and Java code instantly

J→C

JSON to CSV Converter

Convert JSON arrays to CSV with nested object flattening, column selection, and .csv download

TML

TOML ↔ JSON/YAML

Convert between TOML, JSON, and YAML — perfect for Cargo.toml and pyproject.toml

E/D

Encode / Decode Multi-Tool

Base64, Base32, Hex, Binary, URL, and HTML encoding & decoding all in one tool