JSON to TypeScript Interface Generator

Paste sample JSON to generate TypeScript interfaces for it — or reverse the process and create sample JSON from simple interfaces. Need to clean up the JSON first? Run it through the JSON formatter.

Reference

JSON to TypeScript Interface notes

What is JSON to TypeScript Interface?

A JSON to TypeScript interface generator converts sample JSON data into TypeScript interface declarations that describe object properties, nested objects, arrays, primitive values, and nullable fields.

How does the JSON to TypeScript Interface tool work?

The generator parses JSON in the browser, walks through every object and array, infers TypeScript property types, and creates named interfaces for nested object shapes. In reverse mode, it reads simple TypeScript interface declarations and creates sample JSON values for testing or documentation.

When should you use JSON to TypeScript Interface?

  • Generating TypeScript interfaces from REST API responses
  • Creating frontend types for backend JSON payloads
  • Documenting nested JSON objects and arrays
  • Converting sample JSON into typed models for Astro, React, or Node.js projects
  • Creating mock JSON examples from simple TypeScript interfaces
  • Speeding up API integration and contract review

What are the limitations of JSON to TypeScript Interface?

  • Generated interfaces are inferred from sample data, so missing fields cannot be detected automatically
  • Mixed arrays may become union types or unknown[] when the shape is ambiguous
  • Dates are inferred as strings because JSON has no native date type
  • The TypeScript to JSON mode supports simple interfaces and common primitive, array, and nested interface types
  • Advanced TypeScript features such as generics, mapped types, imports, and conditional types are not expanded

JSON to TypeScript Interface examples

json {"id":1,"name":"AdminForge"} -> interface RootObject { id: number; name: string; }
array {"tags":["json","typescript"]} -> tags: string[]
nested {"user":{"email":"hello@example.com"}} -> interface User { email: string; }
reverse interface User { id: number; name: string; } -> { "id": 0, "name": "string" }
Related workflow

Data & Encoding tools

Data & Encoding
Base64 Encoder and Decoder Encode text or images to Base64, decode Base64 strings back to readable text, and preview image data URLs in the browser.
Data & Encoding
JSON Formatter & Validator Format, validate, pretty print, and minify JSON data in your browser for API responses, configuration files, and debugging.
Data & Encoding
URL Encoder and Decoder Encode and decode URLs, query strings, and text safely for web requests, links, and browser navigation.
Data & Encoding
Timestamp Converter Convert Unix timestamps, ISO dates, local time, UTC time, and timezone offsets directly in your browser.
Data & Encoding
YAML Formatter and YAML to JSON Format simple YAML, convert YAML to JSON, and convert JSON back to readable YAML for configs and manifests.
Data & Encoding
HTML Entity Encoder and Decoder Encode text as HTML entities, decode entities back to text, and safely prepare snippets for markup.
Security & Identity
JWT Decoder and Encoder Decode JWT tokens, inspect JSON payloads, verify signatures with a secret, and generate HS256 tokens locally in your browser.
Automation & Patterns
Cron Expression Builder Build readable cron expressions for scheduled jobs and translate minute, hour, day, month, and weekday fields into plain English.
Security & Identity
UUID v4, v7 and v5 Generator Generate UUID v4, sortable UUID v7, namespace UUID v3/v5, GUID, URN, and hyphenless identifiers, then validate UUID strings locally.
Sharing
Custom QR Code Generator Create custom QR codes for URLs, Wi-Fi, vCard, email, SMS, events, and locations with a logo, gradients, module shapes, contrast check, and PNG, SVG, JPEG, or WebP export.
Security & Identity
Hash Generator Generate SHA-1, SHA-256, SHA-384, SHA-512, and BCrypt hashes from text for checksums, password hashing, and integrity checks.
Automation & Patterns
Regex Tester & Debugger Test, debug and replace with regular expressions. Supports Match/Test/Replace modes, positional and named groups, replacement patterns ($1, $&), global matching and detailed match reports.
Security & Identity
Password Generator Generate secure random passwords with customizable length, uppercase, lowercase, digits, and symbols for strong credentials.
Text & Documents
Text and JSON Diff Checker Compare two text or JSON snippets side by side and review added, removed, and changed lines locally.
Network & Web
HTTP Headers Analyzer Parse HTTP headers into a table and highlight cache, security, CORS, and content negotiation signals.
Network & Web
CIDR and IP Subnet Calculator Calculate IPv4 network ranges, masks, usable hosts, broadcast addresses, and CIDR prefix details.
Design
Color Converter and Contrast Checker Convert HEX, RGB, and HSL colors and check WCAG contrast ratios for accessible UI color pairs.
Network & Web
User Agent Parser Parse browser user agent strings into browser, engine, operating system, device, and bot hints.
Text & Documents
SQL Formatter Format SQL queries with readable indentation, keyword casing, and line breaks for debugging and reviews.
Text & Documents
Markdown Preview Preview Markdown as HTML, inspect generated markup, and copy rendered HTML without sending text to a server.