# JSON to TypeScript

> Infer TypeScript interfaces from a JSON sample. Nested objects become named interfaces, and keys missing from some objects in an array are optional. Conversion stays in the tab.

Runs in your browser. Nothing is uploaded.

[Convert](https://toolbuddy.dev/categories/convert.md)

## About this tool

Infer TypeScript from a JSON sample. Objects become named interfaces. Keys missing from some objects in an array are optional. Values that disagree become a union, including null.

How to use: paste JSON, copy the interfaces. A root array of objects is exported as type Root. Empty objects become Record<string, unknown> and empty arrays become unknown[]. This is a starting point, not enums, generics, or a JSON Schema compiler.

Example: {"id":1,"name":"Ada","address":{"city":"London"}} yields interface Root and interface Address. Related: JSON to JSON Schema for a schema draft, JSON to Code for JS, Python, or PHP literals.

## Related Convert tools

- [JSON ↔ YAML](https://toolbuddy.dev/tools/json-yaml.md): Convert JSON to YAML and YAML back to JSON in the browser. Paste a config, Kubernetes snippet, or API fixture and copy the other format. Parsing uses js-yaml locally. Documents are never posted to a converter.
- [JSON ↔ TOML](https://toolbuddy.dev/tools/json-toml.md): Convert JSON objects to TOML and TOML documents back to JSON in the browser. Handy for Cargo.toml, pyproject, and app config fragments. Parsing stays on-device.
- [JSON ↔ XML](https://toolbuddy.dev/tools/json-xml.md): Convert JSON objects to XML and XML documents back to JSON. Useful for SOAP leftovers, RSS, and mixed API stacks. XML is parsed with the browser DOMParser so payloads stay on the device.
- [JSON ↔ CSV](https://toolbuddy.dev/tools/json-csv.md): Turn an array of JSON objects into CSV, or parse CSV headers into JSON objects. Quote-aware parsing runs in the tab so spreadsheets of IDs and emails are not uploaded to a conversion service.
- [JSON to SQL](https://toolbuddy.dev/tools/json-sql.md): Turn a JSON object or array of objects into SQL INSERT statements. Set a table name, copy the query, and keep rows on the device instead of pasting fixtures into a hosted converter.
- [CSV ↔ TSV](https://toolbuddy.dev/tools/csv-tsv.md): Convert comma-separated values to tab-separated values and back, preserving quoted fields. A small delimiter swap for dumps you would rather not paste into a spreadsheet SaaS.