Paste or import JSON
Use a single object, nested object, or collection of records. The parser validates size, nesting depth, and structure. JSON Lines mode merges up to 1,000 sample records.
DEVELOPER TOOLS / DATA MODELS
JSON to Code Generator
Paste JSON. Get clean, typed models for your favorite language—complete with nested structures, optional fields, and source-ready exports.
TypeScriptDartJavaC#PythonGo
01 · INPUT
Your JSON
Paste, drag & drop, or import .json / .jsonl samples (up to 2 MB).0 B
02 · GENERATED CODE
Typed output
ApiResponse.ts
Loading model preview…Select a language to generate code.—
TypeScript types · no runtime dependency
Ready. Your JSON is processed entirely on this device.
Saved workspace data is damaged. The original bytes have been preserved.
0Model classes
0Nodes inspected
0Max depth
0Sample records
Structure explorer
Fields are inferred from the supplied JSON. For arrays of objects, missing keys become optional.
Understand your models
- Type inference describes your example, not every possible API response.
Privacy first
No server or API is contacted. Browser storage is optional; exports are saved to your device.
Dependencies
Java targets Jackson annotations, Python targets Pydantic v2. TypeScript, Dart, C#, and Go target their standard language toolchains.
HOW IT WORKS
Models without the busywork
Choose your language
Switch between six generators, or merge JSON Lines samples to infer optional properties from multiple responses.
Copy or export
Download the active file, original JSON, or a ZIP containing every language model, JSON Schema and generation notes.
Frequently asked questions
How do I infer models from multiple API responses?
Choose JSON Lines mode and paste one JSON object per line, up to 1,000 records. Missing properties become optional in generated models. Arrays in normal JSON mode are also inferred across representative elements.
What is the JSON Schema export?
Download a Draft 2020-12 schema representing the inferred types, nullable options, and required properties. The schema is an approximation from samples, not a replacement for a formally maintained API contract.
Are my API responses uploaded?
No. Parsing and generation happen inside your browser. Turn off “Remember in this browser” to avoid local autosave.
Can generated types validate all possible JSON responses?
No. Types are inferred from your sample. Arrays with varying object keys produce optional fields. For complete contracts, review against your API schema and test with real data.
Which models need additional packages?
The Python output uses Pydantic v2 and Java models use Jackson annotations. The others target standard language features. Generated code is a starting point and should be reviewed before production use.
What are the file-size limits?
Input JSON is capped at 2 MB, nesting at 24 levels, and object fields at 160 per object. Long arrays are sampled across their length for inference, and this is disclosed in the generation notes.