JSON to TypeScript Converter
ConvertersGenerate TypeScript interfaces from a JSON object instantly in your browser. Powered by quicktype-core. Prettier-formatted output. UML class diagram view. Client-side.
JSON →
TypeScript
JSONjson
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TypeScripttypescript
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Input: 315 chars
About JSON to TypeScript Converter
The JSON to TypeScript converter uses `quicktype-core` with `just-types: true` to generate TypeScript interface declarations (no Convert class, no runtime helpers — pure types). The output is formatted with Prettier for clean, idiomatic TypeScript. A UML class diagram panel visualises the inferred type hierarchy. Edit JSON and TypeScript updates live.
Features
- ✓Powered by quicktype-core with just-types mode (interfaces only)
- ✓Output formatted with Prettier for idiomatic TypeScript
- ✓No Convert class — clean, paste-ready interface declarations
- ✓Infers optional vs required properties from JSON samples
- ✓UML class diagram view shows the inferred type hierarchy
- ✓Handles nested objects → nested interfaces
- ✓Handles arrays → typed array properties
- ✓Union types inferred from varied JSON values
- ✓Download generated TypeScript as a .ts file
- ✓Copy output to clipboard in one click
- ✓Web Worker processing — never blocks the UI
- ✓100% client-side — data never leaves your browser
Common Use Cases
- Generating TypeScript interfaces from JSON API responses for typed fetch calls
- Creating types for JSON configuration files in TypeScript projects
- Scaffolding TypeScript model interfaces from JSON database exports
- Reverse-engineering JSON payloads to TypeScript types for legacy API integrations
- Quickly typing arbitrary JSON blobs when building TypeScript apps
Frequently Asked Questions
QDoes the output include runtime code?
No — quicktype is configured with just-types, so the output contains only TypeScript interface and type declarations. No Convert class or validation helpers are included.
QHow are optional properties inferred?
If a key is missing from some objects in a JSON array, quicktype marks the property as optional (?:).
QIs my data sent to a server?
No. quicktype-core runs in a Web Worker inside your browser.