JSON to code generators
When you consume a JSON API, the first job is usually to describe its responses as types in your own language. These generators infer that model from a sample document. Objects become interfaces, classes, structs or records, arrays become typed lists, and nested objects get their own named types.
Inference can only see the sample you give it. A field missing from one element of an array can be marked optional, and a null field can be typed as nullable. A property that never appears in the sample cannot be generated at all. Numbers need judgment too. JSON has a single number type, so a generator picks an integer or floating-point type from the values it sees. Paste a representative response, ideally several array items with the optional fields filled in. Then review names and nullability before you commit the result.
Static types are erased or unchecked at runtime, so outside data can still fail to match them. Runtime validators close that gap. The Zod and Pydantic generators produce schemas that check input as it is parsed, and a JSON Schema can validate the same payload in any language. Every generator here runs in your browser, so private API responses are never uploaded.
All JSON to code generators
- →tsJSON to TypeScriptTurn a JSON sample into TS interfaces with nested types and optional fields.
- →zJSON to ZodInfer a Zod v4 schema with named schemas for nested objects.
- →pyJSON to PydanticInfer Pydantic v2 models with nested classes from sample JSON.
- →goJSON to GoTyped structs with json tags and optional field detection.
- →javaJSON to JavaTurn sample JSON into Java 17 records or POJO classes.
- →C#JSON to C#Create nullable C# models with nested types and JSON attributes.
- →ktJSON to KotlinInfer data classes, nullable fields and kotlinx.serialization names.
- →rsJSON to RustBuild nested Rust structs with Option, Vec and Serde derives.
- →swiftJSON to SwiftGenerate Codable structs with optionals, arrays and CodingKeys.
- →phpJSON to PHPCreate typed PHP 8 DTO classes and JSON key maps.
- →dartJSON to DartGenerate null-safe Dart classes with fromJson and toJson methods.
Related guides
- JSON to TypeScript: how to generate types from JSONTurn a JSON sample into TypeScript interfaces with nested objects, arrays, optional props and unions, and see why you still need runtime validation.
- JSON data types explained with examplesJSON has exactly six data types. Here is what each one allows, how they map to JavaScript and Python, and the precision and null bugs that show up in production.
- JSON Schema: a complete guide with examplesJSON Schema draft 2020-12 from the ground up: core keywords including const, combinators, $ref reuse, and how to generate and validate schemas in code.