JSON to Code Generator
Paste JSON and generate strongly-typed code in your language of choice.
Click "Generate" to see outputAbout JSON to Code Generator
The JSON to Code Generator transforms raw JSON payloads into strongly-typed data structures across multiple languages. Paste any JSON object or array and instantly receive Go structs, TypeScript interfaces, Rust structs with serde attributes, or Java classes with Jackson annotations.
Type safety is the primary goal. Instead of manually mapping JSON fields to types — a tedious and error-prone process — this tool reads your JSON structure and generates idiomatic code that matches the target language's conventions. Nested objects become nested types, arrays become typed slices or vectors, and nullable fields are handled according to each language's idioms.
For Go, the generator produces structs with `json:"field_name"` tags and supports omitempty for optional fields. TypeScript output generates interfaces with optional `?` markers. Rust output includes `#[derive(Debug, Deserialize, Serialize)]` and serde rename attributes. Java output produces POJOs with `@JsonProperty` annotations and proper getters and setters.
Field name conversion follows best practices: snake_case JSON keys become PascalCase in Go and Rust structs, camelCase in TypeScript, and PascalCase in Java. The tool preserves numeric precision — large integers use int64 or i64 rather than float types unless the JSON shows decimals.
For complex or deeply nested JSON, the tool can split output across multiple type definitions. You can also provide a root type name and the generator will name all inferred types consistently, making the output ready to drop directly into your codebase without additional editing.
By eliminating manual mapping, this tool reduces a common source of runtime bugs and serialization errors. It is especially useful when integrating third-party APIs where the response schema is known but no SDK exists.
Frequently Asked Questions
What languages does JSON to Code support?
Go, TypeScript, Rust, and Java. Each output uses the language's standard serialization library — encoding/json for Go, serde for Rust, Jackson for Java, and built-in JSON types for TypeScript.
How does the tool handle null or optional fields?
For Go and Rust, optional fields are detected when the JSON value is null or when a field appears inconsistently across array items. Go uses omitempty tags, Rust uses Option<T>, TypeScript uses optional ? markers, and Java relies on null checks.
Can I control the generated type names?
Yes. You can provide a root type name and the tool will derive child type names by appending prefixes. If no name is given, the tool generates generic names like Root, Item, NestedItem based on the structure.
What happens if my JSON is malformed?
The validator rejects invalid JSON before generation begins and highlights the syntax error location. Only well-formed JSON proceeds to code generation.
Does the tool preserve the original JSON key order?
Yes. The generated types maintain the field order from the input JSON, making the output predictable and consistent with the source data.