JSON to TypeScript Converter
Convert JSON samples into TypeScript interfaces and type definitions.
Why Convert JSON to TypeScript?
Working with untyped REST APIs, webhook payloads, and configuration files in TypeScript often leads to tedious manual interface writing. QuietJSON inspects your sample JSON payloads and automatically derives strict, compile-ready TypeScript interfaces.
Our converter analyzes primitive arrays (string[], number[]), infers optional properties when items in an array have varying schemas (optionalProp?: string), and safely quotes non-standard identifiers.
How to Use
- Paste your raw JSON object or array into the left editor (or click Sample JSON to test).
- Optionally set the root interface name (default:
RootObject) and toggle theexportkeyword. - Click Generate TypeScript.
- Click Copy to copy the types into your code editor, or ↓ Download .ts to save a TypeScript definitions file.
Frequently Asked Questions
How does QuietJSON handle nested JSON objects when generating TypeScript?
QuietJSON recursively inspects nested JSON structures and outputs cleanly indented nested object types or interfaces, preserving exact property hierarchies without name collision risks.
What happens when an array of objects has missing or optional fields?
QuietJSON inspects all objects in an array, computes the union of all keys, and automatically appends the TypeScript optional modifier (?) to any properties that are present in some objects but missing in others.
How are non-standard property names like hyphens or numbers handled?
Keys that contain hyphens, spaces, leading digits, or reserved JavaScript keywords (such as 'first-name', '123', or 'default') are automatically enclosed in quotes so the generated TypeScript code compiles cleanly without syntax errors.
Is my JSON payload uploaded to a server for TypeScript generation?
No. QuietJSON runs entirely client-side in your browser using pure JavaScript. Your JSON data never leaves your device, making it safe for proprietary schemas, auth payloads, and sensitive customer data.
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