Developer Tools That Just Work
Free online developer tools — JSON formatter, TypeScript generator, Java/Python/Go class generator, JWT decoder, UUID generator, and more. Everything runs in your browser — no accounts, no servers.
All Tools
15 free developer tools — 100% client-side, no data sent to servers.
JSON Tools
JSON Formatter
Pretty-print and beautify JSON with syntax highlighting and indentation control.
JSON Validator
Validate JSON syntax instantly with detailed error messages and line numbers.
JSON Diff
Compare two JSON files side-by-side with a syntax-aware unified diff view.
JSON Compare
Deep structural comparison showing added, removed, and changed fields.
JSON Minifier
Remove whitespace and compress JSON to reduce payload size.
JSON Prettifier
Transform compact JSON into human-readable indented format.
JSON Schema Generator
Generate a JSON Schema from any JSON. Detects types, formats, and nested structures.
Code Generators
JSON → TypeScript
Generate TypeScript interfaces or type aliases from JSON with nested type support.
JSON → Java Class
Generate Java POJOs from JSON with getters/setters and Jackson annotation support.
JSON → Python Class
Generate Python dataclasses or Pydantic models from JSON with type hints.
JSON → Go Struct
Generate Go structs from JSON with JSON tags, proper types, and nested structs.
Utilities
JWT Decoder
Decode JWT tokens and inspect header, payload, and expiry claims.
Base64 Encoder/Decoder
Encode or decode Base64 strings. Supports standard and URL-safe variants.
UUID Generator
Generate UUID v1, v4, and v5. Bulk generation with multiple format options.
Timestamp Converter
Convert Unix timestamps to dates and vice versa with live mode.
Why JSONDev.in?
Built on the right principles.
100% Private
All tools run entirely in your browser. No data is ever sent to any server.
Instant Results
Real-time processing as you type. No buttons to click, no waiting.
Always Available
Served globally via AWS CloudFront CDN with 99.99% uptime.
Developer-First
Built by developers for developers. Clean UI, keyboard shortcuts, file upload.