How do I use the JSON to TypeScript interfaces?
- Paste a representative JSON sample.
- Name the root type.
- Copy the interfaces into your project and adjust optional fields.
JSON to TypeScript interfaces: frequently asked questions
How are nested objects handled?
Each nested object becomes its own interface, named after its key.
What about arrays of mixed types?
They become union arrays, e.g. (string | number)[].
How do I mark optional fields?
One sample cannot show which fields are optional. Add ? to fields that may be missing.
Does it support null?
Yes, null values are typed as null. Widen them, e.g. string | null, if they can hold a value.
Should I use zod instead?
For data from outside your app, a runtime validator such as zod is safer; types alone do not check data at runtime.
Are duplicate shapes merged?
Identical object shapes reuse the same interface.
Is my JSON uploaded?
No. Generation runs in your browser.
Does it handle large JSON?
Yes, within your browser’s memory.
Is there an API for this tool?
Selected tools are available through a rate-limited public API. Contact us if you need higher volumes.
Is the json to typescript interfaces free?
Yes. It is free with no sign-up and no usage limits for normal use.