JSON to Types

JSON sample

Generated types

interface Owner {
  name: string
  role: string
}

interface Root {
  project: string
  version: number
  active: boolean
  tags: string[]
  owner: Owner
  notes: null
}

Nested object names are derived from their key; array element types are inferred from the array's first item. Review field names and types before relying on the output for anything beyond a starting point.

About the JSON to Types

Paste a JSON sample and get a matching TypeScript interface, Java class, or C# class back — nested objects are broken out into their own named types automatically instead of one flat blob.

It's built for the moment you have a real API response and need a matching model to write against, without hand-transcribing every field and guessing at nested shapes. Point it at an actual response — not a schema doc that might be stale — and get a starting-point model in seconds, ready to review and adjust rather than write from scratch.

How to Use the JSON to Types

1

Paste a representative JSON sample (a real API response works best).

2

Pick a target language — TypeScript, Java, or C#.

3

Copy the generated interface/class definitions, reviewing nested type names as needed.

Frequently Asked Questions

Is my JSON sample uploaded anywhere?

No — this is the reason the tool exists in this form. Pasting a real API response to generate a model is exactly the kind of paste people don't want leaving their machine, so the whole thing runs as plain JavaScript in your browser.

How are nested objects named?

Each nested object becomes its own interface/class, named after the key it was found under (e.g. an "owner" field becomes an Owner type). If two different keys produce the same generated name with different shapes, a numeric suffix is added to keep them distinct.

How are array element types decided?

From the array's first item only — differing shapes across other items in the same array aren't merged or unioned. Treat the output as a solid starting point to review, not a guaranteed-complete model.

Does it detect optional or nullable fields?

Not automatically — a field's type is inferred from whatever value is present in the sample. If a field can be `null` or missing in other real responses, mark it optional/nullable yourself in the generated output based on what you know about the API.