AnyTool
Your files never leave your device. All processing happens locally in your browser.

How do I generate TypeScript interfaces from JSON?

Paste JSON into AnyTool and it generates clean TypeScript interfaces and types instantly — nested objects become separate named interfaces, optional and union types are detected, and you can choose interface or type output. It runs entirely in your browser, no upload.

  • Nested objects → separate named interfaces
  • Optional (?), nullable, and union-type detection
  • Interface vs type alias output and readonly options
  • Live as-you-type generation with copy and download
  • 100% in-browser — no upload, works offline

What is

JSON to TypeScript

Generating TypeScript from JSON infers static types from a sample JSON document, producing interfaces or type aliases that describe its shape. This gives compile-time safety for API responses and config files without writing the types by hand.

Developer Tools

Related terms

TypeScriptInterfaceType InferenceJSONAPI Types

Frequently Asked Questions

No — generation happens entirely in your browser.

The converter runs client-side with a self-hosted engine, so your JSON never leaves the browser, there is no signup or paywall, and it works offline after first load.

Yes — each nested object becomes its own named interface.

Nested objects are extracted into separate named interfaces and arrays are typed as element arrays, so the output is clean and reusable rather than one giant inline type. Optional and union shapes are detected across array elements.

Yes — toggle between interface declarations and type aliases.

You can output either interface or type-alias declarations, control naming conventions, and add readonly modifiers, then copy the result or download it as a .ts file.

Detailed Explanation

Methodology

How JSON to TypeScript Conversion Works

AnyTool infers TypeScript types from a sample JSON document, extracting nested objects into separate named interfaces and typing arrays by element type. It detects optional (?) and nullable properties, unions differing shapes across array elements, and falls back to unknown for empty or heterogeneous arrays. Users can toggle interface vs type-alias output, choose naming conventions and readonly modifiers, and copy or download the generated .ts file — all updating live as the JSON is edited.

  • Nested objects to separate named interfaces
  • Optional, nullable, and union detection
  • Interface vs type alias and readonly options
  • Identifier sanitization for non-standard keys
  • Live generation with copy and download
Privacy & Security

Privacy and Offline Use

Generation runs entirely client-side with a self-hosted engine and no runtime CDN, so JSON never leaves the browser, there is no signup or paywall, and the tool works offline after first load.

JSON to TypeScript: AnyTool vs typical tools
CapabilityAnyToolTypical tools
Nested named interfacesYesYes
Optional/union detectionYesPartial
Interface vs type toggleYesSometimes
Processing locationIn-browserSometimes server/CDN
No signup / no paywallYesSometimes gated

Capabilities reflect the live AnyTool tool; competitor behavior varies by service.