About jsonsmith.dev
A fast, beautiful, privacy-first JSON toolkit for developers. Format, validate, minify, diff, and convert JSON — entirely in your browser.
100% Client-Side
Your JSON data never leaves your browser. Zero network requests for processing. No server, no database, no data collection.
Instant Performance
All operations run locally in JavaScript. Format megabytes of JSON in milliseconds. No waiting for server responses.
Full-Featured Editor
Powered by Monaco (the engine behind VS Code). Syntax highlighting, bracket matching, code folding, and real-time validation.
Free Core Tools
No ads, no paywalls on core tools. Format, validate, minify, diff, and convert JSON — free, no sign-up required.
Why We Built This
Most online JSON formatters either send your data to a server, show intrusive ads, or both. After the jsonformatter.org security breach in November 2025, it became clear that developers need a JSON tool they can trust.
jsonsmith.dev is our answer: a modern, open, privacy-first toolkit where your data stays exactly where it should — in your browser.
Tools Included
- Formatter / Beautifier — Pretty-print JSON with configurable indentation
- Validator — Real-time syntax checking with line numbers
- Minifier — Compress JSON by removing whitespace
- Tree Viewer — Interactive collapsible tree visualization
- Diff Tool — Compare two JSON objects side by side
- JSON → TypeScript — Generate TypeScript interfaces from JSON
More from Starmorph
jsonsmith.dev is built and maintained by Starmorph. If you find it useful, check out our other tools: Mermaid Editor — a free online Mermaid diagram editor with AI assistance, and Pixelmuse — an AI image studio for thumbnails and product art.
Keyboard Shortcuts
| Shortcut | Action |
|---|---|
| Ctrl+Shift+F | Format / Beautify JSON |
| Ctrl+Shift+M | Minify / Compact JSON |