Paste representative JSON
Include nested objects and realistic array values so generated types reflect actual data.
Developer tools
JSON to TypeScript Generator
Generate TypeScript interfaces from JSON
TypeScript output
The result will appear here after you run the tool.
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About this tool
About this tool
JSON to TypeScript creates readable interface definitions by inspecting a representative JSON sample for objects, nested properties, and array shapes. Generation occurs inside your browser, with options for root name and optional properties.
Paste representative JSON to create readable TypeScript interfaces for objects, nested properties, and arrays. Configure the root type name and optional property behavior.
Built for daily work
- Create frontend models from API samples.
- Start typed webhook payload definitions.
- Generate interfaces for test fixtures.
- Document configuration objects in TypeScript projects.
How to use this tool
How to use this tool
Set naming options
Choose the root type name and whether properties should be optional.
Review inferred types
Sample based generation cannot discover absent values or every possible union type.
Key features
Key features
Nested type generation
Nested objects become named TypeScript definitions.
Array inference
Arrays generate primitive, object, or union item types based on observed values.
Naming cleanup
Invalid property identifiers are quoted and generated type names are converted to PascalCase.
Practical use cases
Practical use cases
- Create frontend models from API samples.
- Start typed webhook payload definitions.
- Generate interfaces for test fixtures.
- Document configuration objects in TypeScript projects.
Private by default
For local tools, input is processed in your browser and is not sent to application analytics.
Data processing noticeTechnical details
Technical details
OutputTypeScript interfaces or type aliases
NamingPascalCase generated types
ArraysObserved item type inference
ProcessingLocal browser processing
Limitations and important notes
Limitations and important notes
- One sample cannot identify every optional property or union variation.
- Semantic types such as Date, URL, UUID, and branded identifiers require manual editing.
- Circular structures cannot exist in JSON and are not generated.
Frequently asked questions
Frequently asked questions
No. They reflect only the supplied sample. Test additional responses and adjust optional or union types.
A null sample produces the null type. Use additional samples or edit the output when a property can also hold another type.
Keys that are not valid identifiers are emitted as quoted property names.
Related guides and solutions
Related guides and solutions
How to convert JSON to TypeScript safely
A guide to generating TypeScript types from JSON: interfaces, unions, nullability, and keeping types in sync with APIs.
Learn moreConvert JSON to TypeScript interfaces in one paste
Typing API responses by hand wastes time and drifts from the real shape. The [JSON to TypeScript tool](tool:json-to-typescript) generates interfaces from a JSON sample instantly, locally.
Learn moreHow to format and validate JSON correctly
A practical guide to indentation, syntax validation, key order, parser errors, and safe output review.
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